JP2008026399A - Charging member cleaning roll, charging device, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charging member cleaning roll capable of efficiently removing substance adhering to the surface of a charging member and further maintaining excellent cleaning performance over a long term, and capable of preventing an image defect from being caused by staining due to the adhesion and accumulation of toner left after transfer and a foreign matter on the surface of the charging member, and to provide a charging device using the charging member cleaning roll, a process cartridge and an image forming apparatus. <P>SOLUTION: The charging member cleaning roll has a core, and an elastic layer which is provided on the outer peripheral surface of the core, and contains urethane foaming body having an open cell structure, an impact resilience modulus of 15-30% and a hardness of 150-230 N. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a charging member cleaning roll for cleaning a charging member for charging an image carrier, which is applied to an image forming apparatus that forms an image using an electrophotographic system. The present invention also relates to a charging device, a process cartridge, and an image forming apparatus using the charging member cleaning roll.

  In an electrophotographic image forming apparatus, a photoreceptor, which is an image carrier, is charged by discharging, and then the surface of the photoreceptor is exposed to form a latent image, and toner is supplied to the latent image to supply toner. Form an image. The toner image formed on the photosensitive member is transferred to a recording paper or the like, and fixed on the recording paper by receiving heat and pressure. In addition, since there is residual toner that is not transferred on the surface of the photoconductor after the toner image is transferred, the surface of the photoconductor is cleaned by a cleaning member such as a cleaning blade or a cleaning brush before the next charging step. The

  In such an image forming apparatus, a charging roll has been put to practical use as a member for uniformly charging the surface of the photoreceptor. The charging roll charges the surface of the photosensitive member by contacting the photosensitive member in a state where a voltage is applied, and has an advantage that ozone and power can be reduced.

  However, the transfer residual toner remaining on the surface of the photoconductor after the transfer of the toner image is not completely removed in the cleaning process and enters the nip portion between the charge roll and the photoconductor, so that the transfer residual toner adheres to the charge roll. There is a problem of doing. In particular, when a toner having a polarity opposite to that of the charging roll or a toner additive is present, the toner is attracted electrostatically and easily adheres to the surface of the charging roll.

  Further, in addition to the transfer residual toner, foreign matters such as carrier and paper dust attached to the surface of the photoreceptor adhere to the surface of the charging roll and contaminate the charging roll. If transfer residual toner or foreign matter adheres to the surface of the charging roll, the resistance of the attached portion increases, and the photosensitive member is liable to be charged poorly. Further, when contamination due to adhesion of transfer residual toner or foreign matter is continued for a long time, the charging failure of the photosensitive member due to uneven resistance of the charging roll increases, causing image quality defects that lead to significant density unevenness.

  In order to prevent image quality defects due to adhesion of transfer residual toner or foreign matters to the charging roll as described above, a method of attaching a cleaning member to the charging roll for the purpose of removing the deposit has been conventionally attempted.

  For example, JP-A-2-272594 proposes using a roll-like sponge material as a cleaning member, but it is sufficient to continuously remove residual toner and foreign matter adhering to the surface of the charging roll. It has a problem that cannot be said.

  Further, in JP-A-5-297690 or JP-A-2004-361916, a roll sponge material or a resin foam is used as a cleaning member, and a mechanism for contacting and separating the charging roll and the cleaning member or a cleaning member is shaken. A measure for improving the removal of deposits on the charging roll by providing a moving mechanism has been proposed. However, the provision of such a mechanism has the problem of increasing the size and cost of the apparatus. Yes.

  In recent years, there has been an increasing demand for higher image quality, and toners having a reduced particle size and a spherical shape have been put into practical use. However, the toner having a small particle size and a spherical shape as described above has a problem that it easily passes through the cleaning blade in the cleaning process and easily causes a cleaning failure. In order to prevent the toner remaining on the photosensitive member from being not cleaned in this way from adhering and accumulating on the charging roller, it is necessary to clean the surface of the charging roller.

JP-A-2-272594 JP-A-5-297690 JP 2004-361916 A

  In view of the above-described problems of the prior art, the present invention can efficiently remove substances adhering to the surface of the charging member and maintain good cleaning performance over a long period of time. Another object of the present invention is to provide a charging member cleaning roll capable of preventing the occurrence of image defects due to contamination caused by adhesion and accumulation of foreign substances. Another object of the present invention is to provide a charging device, a process cartridge, and an image forming apparatus using the cleaning roll for a charging member.

The above problem is solved by the following means. That is,
The charging member cleaning roll of the present invention comprises:
The core,
An elastic layer provided on the outer peripheral surface of the core body, the elastic layer having an open cell structure and including a urethane foam having a rebound resilience of 15% to 30% and a hardness of 150N to 230N When,
It is characterized by having.

  In the charging member cleaning roll of the present invention, it is preferable that the number of bubbles in the open cell structure is in a range of 40/25 mm to 58/25 mm.

  In the cleaning roll for a charging member of the present invention, it is preferable that the urethane foam is a polyester urethane foam.

The charging device of the present invention is
A roll-shaped charging member for charging the member to be charged;
A charging member cleaning roll disposed in contact with the outer peripheral surface of the charging member, the charging member cleaning roll of the present invention,
It is characterized by having.

  In the charging device of the present invention, it is preferable that a DC voltage is applied to the charging member.

The process cartridge of the present invention is
A charging device for charging an image carrier, the charging device of the present invention;
The image carrier, a developing device for developing the electrostatic latent image formed on the image carrier with toner to form a toner image, and the toner remaining on the surface of the image carrier At least one selected from the group consisting of cleaning devices;
It is characterized by having.

The image forming apparatus of the present invention includes:
An image carrier,
A charging device for charging the image carrier, the charging device of the present invention,
An exposure device for forming an electrostatic latent image on the charged image carrier;
A developing device for developing the electrostatic latent image formed on the image carrier with toner to form a toner image;
A transfer device for transferring the toner image to a transfer target;
It is characterized by having.

  According to the present invention, it is possible to efficiently remove substances adhering to the surface of the charging member, and to maintain good cleaning performance for a long period of time, due to adhesion and accumulation of transfer residual toner and foreign matter on the surface of the charging member. It is possible to provide a charging member cleaning roll capable of preventing the occurrence of image defects due to contamination. In addition, a charging device, a process cartridge, and an image forming apparatus using the charging member cleaning roll can be provided.

  Hereinafter, embodiments of the present invention will be described in detail.

(Cleaning roll)
A cleaning roll for a charging member according to an embodiment of the present invention (hereinafter simply referred to as a cleaning roll of the present invention) is a core body and an elastic layer provided on the outer peripheral surface of the core body, and has open cells. An elastic layer having a structure and including a urethane foam having a rebound resilience of 15% to 30% and a hardness of 150N to 230N. Further, if necessary, a conductive adhesive formed by adding conductive particles such as carbon black to a known adhesive or a thermoplastic resin such as ethylene vinyl acetate resin between the core and the elastic layer. Natural rubber latex, butadiene rubber latex, styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, acrylic rubber latex, polyurethane rubber containing conductive particles such as carbon black on the outer surface of the intermediate layer, elastic layer, etc. A surface layer using latex, polyester rubber latex, polyester rubber latex, fluorine rubber latex or the like may be provided.

  In the cleaning roll of the present invention, since the elastic layer includes the specific urethane foam (urethane foam), it is compressed when it comes into contact with the charging member and is compressed and distorted when it comes off. The restoring force for returning to this state acts, and it is possible to effectively and for a long time remove the deposit on the charging member by the force generated when restoring. For this reason, it is possible to efficiently remove substances adhering to the surface of the charging member and to maintain good cleaning performance for a long period of time, which is caused by contamination due to adhesion and accumulation of transfer residual toner and foreign matter on the surface of the charging member. It is possible to prevent the occurrence of image defects.

Next, each member of the cleaning roll will be described.
The core material will be described. As the core material, generally, a molded article such as iron, copper, brass, stainless steel, aluminum, nickel or the like is used. As the core material, a resin molded product in which other conductive particles are dispersed can be used.

  The elastic layer will be described. As described above, the urethane foam constituting the elastic layer has an open cell structure, a rebound resilience of 15% to 30%, and a hardness of 150N to 230N. Here, the “open cell structure” means a structure in which a plurality of bubbles are formed inside the urethane foam and adjacent bubbles are connected to each other.

  The rebound resilience of the urethane foam is from 15% to 30%, preferably from 18% to 27%, and more preferably from 20% to 25%. When the rebound resilience is in the above range, sufficient cleaning performance of the cleaning roll can be obtained.

If the rebound resilience is less than 15%, the force generated when restoring from the compressed state when the cleaning roll is in contact with the charging member is too weak to obtain sufficient cleaning performance, and the transfer residue to the charging member is not obtained. Adhesion and accumulation of toner and foreign matter occur, causing defects in the image.
On the other hand, if the rebound resilience is greater than 30%, even if the cleaning performance is good, the force generated when restoring from the compressed state when the cleaning roll comes into contact with the charging member is too strong, and the charging member surface is shaved. Since the amount increases non-uniformly, if the charging member continues to be used, the charging ability will be reduced non-uniformly, causing streaky defects in the image.

  Here, the resilience modulus of the foamed urethane can be controlled by, for example, the concentration of crosslinking points when the polyurethane is synthesized and the number of bubbles (cells) when the foam is used. The rebound resilience tends to increase as the crosslinking point concentration increases. In addition, the rebound resilience tends to decrease as the number of bubbles (cells) increases in the foam.

  The measurement of the impact resilience is according to JIS K 6400-3. A test piece of 50 × 100 × 100 mm or more is cut out, and a steel ball having a diameter of 16 mm and a mass of 16 g is measured from a height of 500 mm from the upper surface of the test piece. The highest height that was dropped and bounced is expressed as a percentage (%) of the fall height (500 mm).

  The hardness of the polyurethane foam is from 150 N to 230 N, preferably from 170 N to 220 N, and more preferably from 190 N to 210 N. When the hardness is within the above range, sufficient cleaning performance of the cleaning roll can be obtained.

When the hardness is less than 150 N, even if the force generated when the cleaning roll is restored is sufficient, the action of removing the deposit on the charging member is reduced, and good cleaning performance is not exhibited.
On the other hand, if the hardness is greater than 230 N, even if the cleaning performance is good, the surface of the charging member is scratched at an early stage and a fine streak-like defect is generated in the image.

  Here, the hardness of the urethane foam can be controlled by the concentration of crosslinking points when the polyurethane is synthesized. The hardness tends to increase as the crosslinking point concentration increases.

  The hardness is measured in accordance with JIS K 6400-2. A 50 × 380 × 380 mm test piece was cut out and pushed to 75% of the initial thickness in the vertical direction. Press down to 25% of the initial thickness, and read the load when 20 seconds have passed after resting.

  The urethane foam preferably has a number of bubbles (number of foamed cells) in the open cell structure in the range of 40/25 mm to 58/25 mm, more preferably in the range of 45/25 mm to 55/25 mm. More preferably, it is in the range of 48/25 mm to 53/25 mm. When the number of bubbles is within the above range, the cleaning roll can exhibit good cleaning performance.

If the number of bubbles is less than 40/25 mm, the cleaning roll itself may increase the action of rubbing the deposits on the charging member against the surface of the charging member, which may worsen the contamination of the surface of the charging member.
On the other hand, if the number of bubbles is more than 58/25 mm, the strength of the skeleton portion of the foam having a mesh structure composed of fine bubbles is lowered, and the cleaning roll itself is likely to be broken or peeled off. In addition, there is a possibility that the impact resilience decreases and the cleaning performance is impaired. The number of bubbles can be controlled by the addition amount of a known foaming agent such as carbon dioxide gas or a fluorine compound.

  Here, the number of bubbles is measured by visual observation using an optical microscope by drawing a line with a length of 50 mm at an arbitrary position on the surface of a 100 × 100 × 10 mm test piece and counting the bubbles on the line. This is done by determining the number of bubbles per 25 mm. And the said line is drawn at arbitrary three places of a test piece, and let the average value of the value in these three places be the number of bubbles.

  The urethane foam may be either a polyester-based polyurethane foam or a polyether-based urethane foam, but polyester-based foamed urethane is particularly desirable. Since the polyester-based urethane foam has a hydrophilic property, when used as a cleaning roll, it easily adsorbs deposits on the surface of the charging member and exhibits good cleaning performance.

  The polyester-based foam is obtained, for example, using at least polyester polyol and isocyanate. If necessary, other additives such as a foam stabilizer, a catalyst, a curing agent, a crosslinking agent, a foaming agent, a flame retardant, a deterioration preventing agent, a plasticizer, a foam stabilizer, and a conductive agent can be used.

  The polyester polyol will be described. The polyester polyol is preferably a condensed polyester polyol, specifically, an adipate polyol obtained by dihydric acid and a hydroxyl compound, that is, an adipate polyol obtained by dehydrating and condensing them. Examples of the adipate-based polyol include ethylene glycol adipate, diethylene glycol adipate, butylene glycol adipate, trimethylolpropane / diethylene glycol adipate, and the like.

  More specifically, the condensed polyester polyol includes a dicarboxylic acid (for example, adipic acid, glutaric acid, succinic acid, sebacic acid, pimelic acid, suberic acid, etc.) and a diol (for example, ethylene glycol, diethylene glycol, 1,4- And those obtained by condensation with butanediol, 1,6-hexanediol, propylene glycol, neopentyl glycol, etc.) or triol (eg, trimethylolethane, trimethylolpropane, etc.).

  Examples of the condensed polyester polyols include polycarbonate polyols (for example, polycarbonate diols having a structure in which an alkylene group (for example, hexylene group) or a xylylene group is arranged in the main chain via a carbonate bond).

  In addition, polyester polyol may be used individually by 1 type and may be used together with multiple types.

  The amount of the polyester polyol used is preferably 68% by mass or more and 80% by mass or less, and more preferably 70% by mass or more and 78% by mass or less with respect to the total mass of the solid content constituting the elastic layer.

  The isocyanate will be described. Isocyanates include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, tolidine diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, triisocyanate, tetramethylxylene diisocyanate, lysine ester tosiisocyanate. Lysine diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, norbornene diisocyanate and the like can be used. Isocyanate may be used alone or in combination of two or more.

  The amount of isocyanate used is 16% by mass or more and 28% by mass or less, and preferably 18% by mass or more and 26% by mass or less, based on the total mass of the solid content constituting the elastic layer.

  Next, other additives will be described. For example, as the foam stabilizer, an anionic surfactant and a cationic surfactant are preferably mentioned.

  Specific examples of the anionic surfactant include fatty acid soaps such as potassium laurate, sodium oleate and sodium castor oil; sulfates such as octyl sulfate, lauryl sulfate, lauryl ether sulfate and nonyl phenyl ether sulfate; lauryl sulfonate, Sodium alkylnaphthalene sulfonate such as dodecyl sulfonate, dodecyl benzene sulfonate, triisopropyl naphthalene sulfonate, dibutyl naphthalene sulfonate, naphthalene sulfonate formalin condensate, monooctyl sulfosuccinate, dioctyl sulfosuccinate, lauric acid amide sulfonate, oleic acid amide sulfonate, etc. Sulfonates: lauryl phosphate, isopropyl phosphate, Phosphoric acid esters such as phenyl ether phosphate; dialkyl sodium sulfosuccinates, such as sodium dioctyl sulfosuccinate, sodium lauryl sulfosuccinate 2, polyoxyethylene sulfo sulfosuccinate salts such as succinic acid lauryl disodium; and the like.

  Specific examples of the cationic surfactant include laurylamine hydrochloride, stearylamine hydrochloride, oleylamine acetate, stearylamine acetate, stearylaminopropylamine acetate, and other amine salts; lauryltrimethylammonium chloride, dilauryldimethylammonium chloride , Distearyl ammonium chloride, distearyl dimethyl ammonium chloride, lauryl dihydroxyethyl methyl ammonium chloride, oleyl bis polyoxyethylene methyl ammonium chloride, lauroyl aminopropyl dimethyl ethyl ammonium etosulphate, lauroyl aminopropyl dimethyl hydroxyethyl ammonium perchlorate, alkylbenzene dimethyl ammonium Chloride, alkyl trime Quaternary ammonium salts such as Le ammonium chloride; and the like.

  In addition, a foam stabilizer may be used individually by 1 type and may be used together with multiple types.

  The amount of the foam stabilizer used is preferably 1.4% by mass or more and 1.6% by mass, and more preferably 1.4% by mass or more and 1.5% by mass with respect to the total mass of the solid content constituting the elastic layer. .

  Examples of the catalyst include amine compounds and organometallic compounds. Examples of the amine compound include triethylamine, tetramethylethylenediamine, triethylenediamine, and the like. Examples of the organometallic compound include dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dimaleate.

  In addition, a catalyst may be used individually by 1 type and may be used together with multiple types.

  The amount of the catalyst used is preferably 0.47% by mass or more and 0.97% by mass, and more preferably 0.5% by mass or more and 0.95% by mass with respect to the total mass of the solid content constituting the elastic layer. When no catalyst is used, unreacted polymer remains on the cleaning roll, and image defects occur due to bleeding at the contact portion with the charging member.

  Examples of the conductive agent include carbon conductive agents such as ketjen black, acetylene black, oil furnace black, and thermal black, and ionic conductive agents such as ammonium compounds such as tetraethylammonium and stearyltrimethylammonium chloride. Can be mentioned.

  Next, the manufacturing method of a urethane foam is demonstrated. There is no restriction | limiting in particular about the manufacturing method of a urethane foam, Although what is necessary is just according to a conventional method, if the example is shown, it will be as follows. First, after mixing polyol, isocyanate, and other additives as necessary as raw materials, a urethane foam can be obtained by heating and reaction curing.

  Although there is no restriction | limiting in particular about the temperature and time at the time of mixing a raw material, Mixing temperature is 10-90 degreeC normally, Preferably it is the range of 20-60 degreeC. The mixing time is usually about 10 seconds to 20 minutes, preferably about 30 seconds to 5 minutes. Moreover, when making it heat-react and cure, a polyurethane foam can be obtained by making it foam by a conventionally well-known method.

  Here, there is no restriction | limiting in particular about the foaming method, Any methods, such as the method of using a foaming agent and the method of mixing bubbles by mechanical stirring, can be used.

  Next, the suitable form of the cleaning roll of this invention is demonstrated. The cleaning roll may be insulative or conductive. That is, the conductive layer may be insulative or conductive.

  When the cleaning roll of the present invention has conductivity, it may also serve as a charging member that charges the image carrier. In some cases, a cleaning bias is applied. Further, the “conductivity” includes semiconductivity.

Here, the insulating property means a range of 10 ¹² Ωcm or more in volume resistivity. On the other hand, the conductivity means a range of 10 ¹⁰ Ωcm or less in volume resistivity.

  The volume resistivity was measured in accordance with JIS-K-6911 (1995) by using a circular electrode (high probe IP UR probe manufactured by Mitsubishi Yuka Co., Ltd .: cylindrical electrode outer diameter Φ16 mm, ring electrode part Is measured by using a microammeter R8340A manufactured by Advantest and applying a voltage of 100V in an environment of 22 ° C / 55% RH and applying a voltage of 5 sec after application. Thus, the volume resistivity is obtained from the volume resistance.

The method for imparting conductivity to the cleaning roll of the present invention is not particularly limited, such as a method of kneading a conductive material into the elastic layer or a method of spraying a conductive powder. It is desirable to apply an impregnation method in which a cleaning roll is impregnated in a conductive paint adjusted to ³ to 10 ¹⁰ Ω · cm (desirably 10 ⁴ to 10 ⁸ Ω · cm). According to the impregnation method, a cleaning roll having a very stable volume resistivity can be obtained, and the cost can be kept very low. Examples of such conductive paints include those in which carbon is dispersed in urethane, silicon, styrene or the like and dissolved in a solvent (for example, ethyl acetate, toluene, methyl ethyl ketone, or the like).

  Next, the manufacturing method of the cleaning roll of this invention is demonstrated. As a manufacturing method of the cleaning roll, for example, a raw material is injected into a mold and foamed, and a urethane foam having a desired shape is coated on a core material. A urethane foam is slab-molded to obtain a desired shape. Examples of the method include a method of coating the core material after processing by grinding or the like.

(Charging device)
For example, as shown in FIG. 1, the charging device of the present invention includes a charging roll 21 </ b> A for charging a member to be charged (for example, an image carrier), and a cleaning roll disposed in contact with the outer peripheral surface of the charging roll 21 </ b> A. 21B. The cleaning roll of the present invention is applied as the cleaning roll 21B. In the figure, reference numeral 21 denotes a charging device.

  The cleaning roll 21B is in contact with the outer peripheral surface (elastic layer surface), for example, the outer peripheral surface of the charging roll 21A, in a state of being freely contactable and separable, and is installed so as to be reciprocally movable in the axial direction of the charging roll 2. Accordingly, when cleaning is not required (when the image forming apparatus is stopped for a long time), the cleaning roll 21B can be placed away from the charging roll 21A, and the surface of the charging roll 21A can be made uniform. Can be cleaned.

  When the cleaning roll 21B comes into contact with the charging roll 21A, the cleaning roll 21B is disposed in a state of being pressed by the charging roll 21A, and is rotated following the rotation of the charging roll 21A. Thereby, scratch scratches on the charging roll 21A can be prevented.

  In the charging device of the present invention, a member to be charged (for example, an image carrier) can be charged by the charging roll 21A while cleaning the surface of the charging roll by the cleaning roll 21B.

  Then, by applying a cleaning roll described later, it is possible to efficiently remove substances adhering to the surface of the charging member, and to maintain good cleaning performance for a long period of time. It is possible to prevent the occurrence of image defects due to contamination due to adhesion and accumulation of residual toner and foreign matter.

Hereinafter, the charging roll will be described. Note that the reference numerals are omitted.
The charging roll is a contact charging type member, and can suppress a decrease in the film thickness of the image carrier. The contact charging type charging roll charges the surface of the image carrier by applying a voltage to a conductive member brought into contact with the surface of the image carrier.

  Examples of the charging roll include a core and an outer peripheral surface of which an elastic layer and a resistance layer are sequentially formed. Furthermore, a protective layer can be provided outside the resistance layer as necessary.

  The charging roll is preferably disposed in pressure contact with the image holding body so as to be pressed against the image holding body and driven to rotate as the image holding body rotates. Alternatively, a driving unit may be attached to the charging roll and may be arranged to rotate at a peripheral speed different from that of the image holding member.

  Next, each member of the charging roll will be described. As a core, it has electroconductivity and generally molded products, such as iron, copper, brass, stainless steel, aluminum, nickel, are used. In addition, a resin molded product in which conductive particles or the like are dispersed can be used.

  Next, the elastic layer will be described. The elastic layer has, for example, conductivity or semiconductivity, and is generally a conductive material or semiconducting particles dispersed in a rubber material.

  As the rubber material, EPDM, polybutadiene, natural rubber, polyisobutylene, SBR, CR, NBR, silicon rubber, urethane rubber, epichlorohydrin rubber, SBS, thermoplastic elastomer, norbornene rubber, fluorosilicone rubber, ethylene oxide rubber and the like are used.

Examples of the conductive particles or semiconductive particles include carbon black, zinc, aluminum, copper, iron, nickel, chromium, titanium and other metals, ZnO—Al ₂ O ₃ , SnO ₂ —Sb ₂ O ₃ , In ₂ O ₃ — Metal oxides such as SnO ₂ , ZnO—TiO ₂ , MgO—Al ₂ O ₃ , FeO—TiO ₂ , TiO ₂ , SnO ₂ , Sb ₂ O ₃ , In ₂ O ₃ , ZnO, MgO can be used, These materials may be used alone or in combination of two or more.

As the resistance layer and the protective layer, conductive particles or semiconductive particles are dispersed in a binder resin and the resistance is controlled, and the volume resistivity is 10 ³ to 10 ¹⁴ Ωcm, preferably 10 ⁵ to 10 ^12. Ω ^cm , more preferably 10 ⁷ to 10 ¹² Ω cm is preferable. The thickness of the resistance layer and the protective layer is 0.01 to 1000 μm, desirably 0.1 to 500 μm, and more desirably 0.5 to 100 μm.

  As binder resin, acrylic resin, cellulose resin, polyamide resin, methoxymethylated nylon, ethoxymethylated nylon, polyurethane resin, polycarbonate resin, polyester resin, polyethylene resin, polyvinyl resin, polyarylate resin, polythiophene resin, PFA, FEP, A polyolefin resin such as PET, a styrene butadiene resin, or the like is used.

  As the conductive particles or semiconductive particles, the same carbon black, metal, and metal oxide as the elastic layer are used. If necessary, an antioxidant such as hindered phenol and hindered amine, a filler such as clay and kaolin, and a lubricant such as silicone oil can be added.

  As a means for forming these layers, a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, a curtain coating method, or the like can be used.

  Examples of a method of charging the image carrier using a charging roll include a method of applying a DC voltage to the charging roll, or a method of applying a DC voltage and an AC voltage in a superimposed manner. A method of applying this DC voltage. Is desirable. In particular, when the surface of the image carrier is charged only with a DC voltage, no AC voltage is applied, so the amount of current flowing into the image carrier is very small. That is, it is indicated that the pulse discharge to the image carrier is also reduced, and as a result, the etching action on the image carrier (photoreceptor) is reduced and the film loss of the image carrier is suppressed to a small extent.

  On the other hand, the surface of the charging roll is more easily contaminated when only the DC voltage is applied than when the DC voltage and the AC voltage are superimposed and applied to the charging roll. This is because when a DC voltage and an AC voltage are applied in a superimposed manner, positive and negative electric fields continue to be alternately generated on the surface of the charging roll due to the application of the AC voltage. Therefore, it is possible to remove deposits from the surface of the charging roll relatively easily, and use a conventionally known cleaning roll made of a brush-shaped, pad-shaped or roll-shaped resin. Is possible.

  However, when only a DC voltage is applied to the charging roll, since the charging roll surface is always applied with a positive or negative single polarity voltage, a toner having an opposite polarity to the charging polarity or a toner additive, Cleaning performance that satisfies the above-mentioned conventionally known cleaning roll made of a brush-shaped, pad-shaped, or roll-shaped resin that exhibits a state in which foreign matters such as paper dust are easily attached and difficult to remove. However, satisfactory cleaning performance can be obtained by using the cleaning roll of the present invention.

  Here, as the voltage range, the DC voltage is preferably positive or negative 50 to 2000 V, particularly 100 to 1500 V, depending on the required image carrier charging potential. When the AC voltage is superimposed, the peak-to-peak voltage is preferably 400 to 1800 V, preferably 800 to 1600 V, and more preferably 1200 to 1600 V. The frequency of the AC voltage is 50 to 20,000 Hz, preferably 100 to 5,000 Hz.

(Image forming apparatus and process cartridge)

  FIG. 2 is a schematic diagram showing a preferred embodiment of the image forming apparatus of the present invention. An image forming apparatus 100 illustrated in FIG. 2 includes a process cartridge 20 including at least a charging device 21, an exposure device 30, a transfer device 40, and an intermediate transfer member 50 in an image forming apparatus main body (not shown). In the image forming apparatus 100, the exposure device 30 is disposed at a position where the electrophotographic photosensitive member 1 (image holding member) can be exposed from the opening of the process cartridge 20, and the transfer device 40 is interposed via the intermediate transfer member 50. The intermediate transfer member 50 is disposed so that a part of the intermediate transfer member 50 is in contact with the electrophotographic photosensitive member 1.

  The process cartridge 20 is obtained by integrating the electrophotographic photosensitive member 1, the developing device 25, the cleaning device 27, and the fibrous member (flat brush shape) 29 together with the charging device 21 with a mounting rail in a case. The case is provided with an opening for exposure.

  The charging device of the present invention is applied as the charging device 21. The charging device 21 includes the charging roll 21A and the cleaning roll 21B as described above.

  Next, the electrophotographic photosensitive member 1 will be described. FIG. 6 is a schematic cross-sectional view showing a preferred embodiment of the electrophotographic photosensitive member of the present invention. An electrophotographic photosensitive member 1 shown in FIG. 6 includes a conductive support 2 and a photosensitive layer 3. The photosensitive layer 3 has a structure in which an undercoat layer 4, a charge generation layer 5, a charge transport layer 6 and a protective layer 7 are laminated on the conductive support 2 in this order.

  7 to 10 are schematic sectional views showing other preferred embodiments of the electrophotographic photosensitive member of the present invention. The electrophotographic photosensitive member shown in FIGS. 7 to 8 is provided with the photosensitive layer 3 in which the functions are separated into the charge generation layer 5 and the charge transport layer 6 as in the electrophotographic photosensitive member shown in FIG. 9 to 10 show that the charge generation material and the charge transport material are contained in the same layer (single-layer type photosensitive layer 8).

  The electrophotographic photoreceptor 1 shown in FIG. 7 has a structure in which a charge generation layer 5, a charge transport layer 6 and a protective layer 7 are sequentially laminated on a conductive support 2. The electrophotographic photoreceptor 1 shown in FIG. 8 has a structure in which an undercoat layer 4, a charge transport layer 6, a charge generation layer 5, and a protective layer 7 are sequentially laminated on a conductive support 2.

  The electrophotographic photoreceptor 1 shown in FIG. 9 has a structure in which an undercoat layer 4, a single-layer type photosensitive layer 8, and a protective layer 7 are sequentially laminated on a conductive support 2. The electrophotographic photoreceptor 1 shown in FIG. 10 has a structure in which a single-layer type photosensitive layer 8 and a protective layer 7 are sequentially laminated on a conductive support 2.

  In the electrophotographic photoreceptor shown in FIGS. 6 to 10, the undercoat layer 4 is not necessarily provided.

  The photosensitive layer provided in the electrophotographic photosensitive member 1 includes a single-layer type photosensitive layer containing a charge generation material and a charge transport material in the same layer, or a layer containing a charge generation material (charge generation layer) and a charge transport material. Any of the function-separated type photosensitive layers provided separately with the contained layer (charge transport layer) may be used. In the case of the function-separated type photosensitive layer, any of the stacking order of the charge generation layer and the charge transport layer may be the upper layer. In the case of a function-separated photosensitive layer, it is possible to achieve functional separation because it is possible to perform functional separation in which each layer only has to satisfy each function.

  The electrophotographic photosensitive member 1 is not particularly limited, and known ones can be applied. Hereinafter, each element will be described based on the electrophotographic photosensitive member 1 shown in FIG. 6 as a representative example.

  Examples of the conductive support 2 include a metal plate, a metal drum, and a metal belt formed using a metal or an alloy such as aluminum, copper, zinc, stainless steel, chromium, nickel, molybdenum, vanadium, indium, gold, or platinum. Etc. Further, as the conductive support 2, paper, plastic film, belt or the like coated, vapor-deposited or laminated with a conductive polymer, a conductive compound such as indium oxide, or a metal or alloy such as aluminum, palladium, or gold can be used.

  The surface of the conductive support 2 is desirably roughened to a centerline average roughness (Ra) of 0.04 μm or more and 0.5 μm or less in order to prevent interference fringes generated when laser light is irradiated. . When the center line average roughness (Ra) of the surface of the conductive support 2 is less than 0.04 μm, the effect of preventing interference tends to be insufficient because it is close to a mirror surface. On the other hand, if the center line average roughness (Ra) exceeds 0.5 μm, the image quality tends to be insufficient even if a film is formed. When non-interfering light is used as a light source, it is not particularly necessary to roughen the interference fringes, and it is possible to prevent the occurrence of defects due to irregularities on the surface of the conductive support 2, which is suitable for longer life.

  Surface roughening methods include wet honing by suspending an abrasive in water and spraying it on the support, or centerless grinding, in which the support is pressed against a rotating grindstone, and grinding is performed continuously, anodization Processing is desirable.

  Further, as another roughening method, a conductive or semiconductive powder is dispersed in a resin without roughening the surface of the conductive support 2 to form a layer on the surface of the support. Further, a method of roughening with particles dispersed in the layer is also preferably used.

  The anodizing treatment is to form an oxide film on the aluminum surface by anodizing in an electrolyte solution using aluminum as an anode. Examples of the electrolyte solution include a sulfuric acid solution and an oxalic acid solution. However, the intact porous anodic oxide film is chemically active, easily contaminated, and has a large resistance fluctuation due to the environment. Therefore, the pores in the anodized film are sealed with pressurized water vapor or boiling water (a metal salt such as nickel may be added) by volume expansion due to a hydration reaction, and a sealing process is performed to change to a more stable hydrated oxide. .

  The thickness of the anodic oxide film is desirably 0.3 μm or more and 15 μm or less. When this film thickness is less than 0.3 μm, the barrier property against implantation tends to be poor and the effect tends to be insufficient. On the other hand, when it exceeds 15 μm, there is a tendency that the residual potential increases due to repeated use.

  Further, the conductive support 2 may be subjected to treatment with an acidic aqueous solution or boehmite treatment. The treatment with an acidic treatment liquid comprising phosphoric acid, chromic acid and hydrofluoric acid is carried out as follows. First, an acidic treatment liquid is prepared. The mixing ratio of phosphoric acid, chromic acid and hydrofluoric acid in the acidic treatment liquid is such that phosphoric acid is in the range of 10% by mass to 11% by mass, chromic acid is in the range of 3% by mass to 5% by mass, and hydrofluoric acid is 0.00%. The concentration of these acids is preferably in the range of 13.5 mass% to 18 mass%. The treatment temperature is preferably 42 ° C. or more and 48 ° C. or less, but by keeping the treatment temperature high, a thicker film can be formed faster. The film thickness is preferably from 0.3 μm to 15 μm. If it is less than 0.3 μm, the barrier property against injection tends to be poor and the effect tends to be insufficient. On the other hand, when it exceeds 15 μm, there is a tendency that the residual potential increases due to repeated use.

  The boehmite treatment can be performed by immersing in pure water of 90 ° C. or higher and 100 ° C. or lower for 5 minutes or longer and 60 minutes or shorter, or by contacting with heated steam of 90 ° C. or higher and 120 ° C. or lower for 5 minutes or longer and 60 minutes or shorter. . The film thickness is preferably 0.1 μm or more and 5 μm or less. This may be further anodized using an electrolyte solution with low film solubility such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, citrate, etc. Good.

  The undercoat layer 4 is formed on the conductive support 2. The undercoat layer 4 includes, for example, an organometallic compound and / or a binder resin.

  As organometallic compounds, zirconium chelate compounds, zirconium alkoxide compounds, organozirconium compounds such as zirconium coupling agents, titanium chelate compounds, titanium alkoxide compounds, organotitanium compounds such as titanate coupling agents, aluminum chelate compounds, aluminum coupling agents In addition to organoaluminum compounds such as antimony alkoxide compounds, germanium alkoxide compounds, indium alkoxide compounds, indium chelate compounds, manganese alkoxide compounds, manganese chelate compounds, tin alkoxide compounds, tin chelate compounds, aluminum silicon alkoxide compounds, aluminum titanium alkoxide compounds, And aluminum zirconium alkoxide compounds. .

  As the organometallic compound, an organic zirconium compound, an organic titanyl compound, and an organoaluminum compound are particularly preferably used because of low residual potential and good electrophotographic characteristics.

  As the binder resin, polyvinyl alcohol, polyvinyl methyl ether, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, polyamide, polyimide, casein, gelatin, polyethylene, polyester, phenol resin, Examples include known vinyl chloride-vinyl acetate copolymers, epoxy resins, polyvinyl pyrrolidone, polyvinyl pyridine, polyurethane, polyglutamic acid, polyacrylic acid, and the like. When these are used in combination of two or more, the mixing ratio can be appropriately set as necessary.

  The undercoat layer 4 includes vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris-2-methoxyethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltri Methoxysilane, γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-2-aminoethylaminopropyltrimethoxysilane, γ-mercapropropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, β- A silane coupling agent such as 3,4-epoxycyclohexyltrimethoxysilane may be contained.

  In the undercoat layer 4, an electron transporting pigment can also be mixed / dispersed from the viewpoints of lowering the residual potential and environmental stability. Examples of the electron transport pigment include organic pigments such as perylene pigment, bisbenzimidazole perylene pigment, polycyclic quinone pigment, indigo pigment, and quinacridone pigment described in JP-A-47-30330, cyano group, nitro group, Examples thereof include organic pigments such as bisazo pigments and phthalocyanine pigments having electron-withdrawing substituents such as nitroso groups and halogen atoms, and inorganic pigments such as zinc oxide and titanium oxide.

  Among these pigments, perylene pigments, bisbenzimidazole perylene pigments, polycyclic quinone pigments, zinc oxide or titanium oxide are preferably used because of their high electron mobility.

  In addition, the surface of these pigments may be surface-treated with the above coupling agent or binder resin for the purpose of controlling dispersibility and charge transporting property.

  If the amount of the electron transporting pigment is too large, the strength of the undercoat layer 4 is lowered and causes coating film defects. Therefore, the amount is preferably 95% by mass or less, more preferably 90% by mass based on the total solid content of the undercoat layer 4. % Used.

  Further, it is desirable to add various kinds of fine powders of organic compounds or fine powders of inorganic compounds to the undercoat layer 4 for the purpose of improving electrical characteristics and light scattering properties. In particular, white pigments such as titanium oxide, zinc oxide, zinc white, zinc sulfide, lead white, lithopone, inorganic pigments such as alumina, calcium carbonate, barium sulfate, and the like, polytetrafluoroethylene resin particles, benzoguanamine resin particles, Styrene resin particles and the like are effective.

  The added fine powder preferably has a volume average particle diameter of 0.01 μm or more and 2 μm or less. The fine powder is added as necessary, but the addition amount is preferably 10% by mass or more and 90% by mass or less, and 30% by mass or more and 80% by mass or less based on the total solid content of the undercoat layer 4. Is more desirable.

  The undercoat layer 4 is formed using an undercoat layer forming coating solution containing the above-described constituent materials. The organic solvent used in the coating solution for forming the undercoat layer is one that dissolves an organometallic compound or a binder resin and does not cause gelation or aggregation when an electron transporting pigment is mixed and / or dispersed. If it is.

  Examples of the organic solvent include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, and methylene chloride. , Chloroform, chlorobenzene, toluene and the like. These can be used individually by 1 type or in mixture of 2 or more types.

  As a method for mixing and / or dispersing each constituent material, a conventional method using a ball mill, a roll mill, a sand mill, an attritor, a vibrating ball mill, a colloid mill, a paint shaker ultrasonic wave, or the like is applied. Mixing and / or dispersion is performed in an organic solvent.

  As a coating method for forming the undercoat layer 4, a normal method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method is used. be able to.

  The drying is usually performed at a temperature at which the solvent can be evaporated and a film can be formed. In particular, the conductive support 2 subjected to the acidic solution treatment and the boehmite treatment is preferably formed with the undercoat layer 4 because the defect concealing power of the substrate tends to be insufficient.

  The thickness of the undercoat layer 4 is desirably 0.01 μm or more and 30 μm or less, and more desirably 0.05 μm or more and 25 μm or less.

The charge generation layer 5 includes a charge generation material and, if necessary, a binder resin.
Known charge generation materials include azo pigments such as bisazo and trisazo, condensed aromatic pigments such as dibromoanthanthrone, organic pigments such as perylene pigments, pyrrolopyrrole pigments, and phthalocyanine pigments, and inorganic pigments such as trigonal selenium and zinc oxide. Can be used. As the charge generation material, metal and metal-free phthalocyanine pigments, trigonal selenium, dibromoanthanthrone and the like are particularly desirable when a light source having an exposure wavelength of 380 to 500 nm is used. Among them, hydroxygallium phthalocyanine disclosed in JP-A-5-263007 and JP-A-5-279591, chlorogallium phthalocyanine disclosed in JP-A-5-98181, JP-A-5-140472 and special Dichlorotin phthalocyanine disclosed in Kaihei 5-140473 and titanyl phthalocyanine disclosed in JP-A-4-189873 and JP-A-5-43813 are particularly desirable.

Further, among the above hydroxygallium phthalocyanines, in the spectral absorption spectrum, it has an absorption maximum at 810 nm or more and 839 nm or less, the primary particle diameter is 0.10 μm or less, and the specific surface area value by BET method is 45 m ² / What is more than g is desirable.

  The binder resin can be selected from a wide range of insulating resins, and can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. Desirable binder resins include polyvinyl butyral resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin. Insulating resins such as polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin can be mentioned, but are not limited thereto. These binder resins can be used individually by 1 type or in mixture of 2 or more types.

  The charge generation layer 5 is formed by vapor deposition of a charge generation material or a coating solution for forming a charge generation layer containing a charge generation material and a binder resin. When the charge generation layer 5 is formed using a charge generation layer forming coating solution, the blending ratio (mass ratio) of the charge generation material and the binder resin is preferably in the range of 10: 1 to 1:10.

  As a method for dispersing each of the constituent materials in the charge generation layer forming coating solution, a usual method such as a ball mill dispersion method, an attritor dispersion method, a sand mill dispersion method, or the like can be used. At this time, a condition that the crystal form of the pigment is not changed by the dispersion is required. Further, in this dispersion, it is effective to make the particles preferably have a particle size of 0.5 μm or less, more preferably 0.3 μm or less, and even more preferably 0.15 μm or less.

  Solvents used for dispersion include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, and methylene chloride. Ordinary organic solvents such as chloroform, chlorobenzene and toluene. These can be used individually by 1 type or in mixture of 2 or more types.

  When forming the charge generation layer 5 using the coating solution for forming the charge generation layer, the coating methods are blade coating method, wire bar coating method, spray coating method, dip coating method, bead coating method, air knife coating. Ordinary methods such as a method and a curtain coating method can be used.

  The film thickness of the charge generation layer 5 is desirably 0.1 μm or more and 5 μm or less, and more desirably 0.2 μm or more and 2.0 μm or less.

The charge transport layer 6 includes a charge transport material and a binder resin, or a polymer charge transport material.
Examples of charge transport materials include quinone compounds such as p-benzoquinone, chloranil, bromanyl, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, xanthone compounds, benzophenone compounds , Electron transport compounds such as cyanovinyl compounds and ethylene compounds, triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, etc. Examples thereof include, but are not limited to, hole transporting compounds. These charge transport materials can be used singly or in combination of two or more.

  Moreover, as a charge transport material, the compound shown by the following general formula (a-1), (a-2) or (a-3) from a mobility viewpoint is desirable.

In the above formula (a-1), R ¹⁶ represents a hydrogen atom or a methyl group, and n10 represents 1 or 2. Ar ₆ and Ar ₇ are each independently a substituted or unsubstituted aryl group, —C ₆ H ₄ —C (R ³⁸ ) ═C (R ³⁹ ) (R ⁴⁰ ), or —C ₆ H ₄ —CH. ═CH—CH═C (Ar) ₂ is substituted with a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 1 to 3 carbon atoms. And substituted amino groups. R ³⁸ , R ³⁹ and R ⁴⁰ are a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and Ar is a substituted or unsubstituted aryl group.

In the above formula (a-2), R ¹⁷ and R ^{17 ′} each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms, R ¹⁸ , R ^{18 ′.} , R ¹⁹ and R ^{19 ′} are each independently a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, substituted or unsubstituted A substituted aryl group, —C (R ³⁸ ) ═C (R ³⁹ ) (R ⁴⁰ ), or —CH═CH—CH═C (Ar) ₂ , R ³⁸ , R ³⁹ and R ⁴⁰ are each independently A hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, Ar represents a substituted or unsubstituted aryl group. N2 and n3 each independently represents an integer of 0 to 2.

In the formula (a-3), R ₂₁ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a substituted or unsubstituted aryl group, or —CH═CH—CH═. C (Ar) ₂ is shown. Ar represents a substituted or unsubstituted aryl group. R ₂₂ and R ₂₃ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, or A substituted or unsubstituted aryl group is shown.

  Examples of the binder resin used for the charge transport layer 6 include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, and vinylidene chloride. -Acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, and the like. These binder resins can be used individually by 1 type or in mixture of 2 or more types. The mixing ratio (mass ratio) between the charge transport material and the binder resin is preferably 10: 1 to 1: 5.

  As the polymer charge transporting material, known materials having charge transporting properties such as poly-N-vinylcarbazole and polysilane can be used. In particular, polyester polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 have a high charge transport property and are particularly desirable.

  Although the polymer charge transport material alone can be used as a constituent material of the charge transport layer 6, it may be mixed with the binder resin to form a film.

The charge transport layer 6 is formed using a charge transport layer forming coating solution containing the above-described constituent materials.
Examples of the solvent for the coating solution for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, and halogenated fats such as methylene chloride, chloroform and ethylene chloride. Examples thereof include ordinary organic solvents such as aromatic hydrocarbons, cyclic ethers such as tetrahydrofuran and ethyl ether, and linear ethers. These can be used individually by 1 type or in mixture of 2 or more types.

  As a coating method of the coating solution for forming the charge transport layer, a normal method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method should be used. Can do.

  The film thickness of the charge transport layer 6 is desirably 5 μm or more and 50 μm or less, and more desirably 10 μm or more and 30 μm or less.

  In the photosensitive layer 3, additives such as an antioxidant, a light stabilizer, and a heat stabilizer are added for the purpose of preventing deterioration of the photoreceptor due to ozone, an oxidizing gas, or light or heat generated in the image forming apparatus. Can be added.

  Examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds. Examples of the light stabilizer include derivatives such as benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine.

  The photosensitive layer 3 can contain at least one electron accepting substance for the purpose of improving sensitivity, reducing residual potential, reducing fatigue during repeated use, and the like.

Examples of the electron acceptor include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene, Examples include chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, and phthalic acid. Of these, fluorenone-based, quinone-based, and benzene derivatives having electron-withdrawing substituents such as Cl, CN, NO ₂ are particularly desirable.

The protective layer 7 can be comprised with the following resin, for example.
Examples of the resin include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride. -Vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole, polysilane, Polymer charge transport materials such as polyester-based polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 can also be used. Among these, thermosetting resins such as phenol resin, thermosetting acrylic resin, thermosetting silicone resin, epoxy resin, melamine resin, urethane resin, polyimide resin, and polybenzimidazole resin are desirable. Among these, in particular, phenol resin, melamine resin, benzoguanamine resin, siloxane resin, and urethane resin are preferably used, and at the same time in the step of drying the solvent after applying a coating liquid containing these resins or their precursors as a main component. Heat treatment is performed to cure and form an insoluble cured film.

  Examples of the phenol resin include monomers of monomethylolphenols, dimethylolphenols or trimethylolphenols, mixtures thereof, oligomers thereof, or mixtures of these monomers and oligomers. Such phenol resins include resorcin, bisphenol, substituted phenols containing one hydroxyl group such as phenol, cresol, xylenol, paraalkylphenol, paraphenylphenol, and substituted phenols containing two hydroxyl groups such as catechol, resorcinol, hydroquinone, etc. It is obtained by reacting a compound having a phenol structure such as bisphenols such as bisphenol A and bisphenol Z and biphenols with formaldehyde, paraformaldehyde and the like in the presence of an acid catalyst or an alkali catalyst. As a phenol resin, what is generally marketed as a phenol resin can be used. Moreover, as a phenol resin, a resol type phenol resin is desirable. In the present specification, a relatively large molecule having about 2 to 20 repeating molecular structural units is referred to as an oligomer, and a molecule smaller than that is referred to as a monomer.

As the acid catalyst, sulfuric acid, paratoluenesulfonic acid, phosphoric acid and the like are used. Further, as the alkali catalyst, hydroxides or amine catalysts of alkali metals and alkaline earth metals such as NaOH, KOH, Ca (OH) ₂ and Ba (OH) ₂ are used.

  Examples of the amine catalyst include, but are not limited to, ammonia, hexamethylenetetramine, trimethylamine, triethylamine, and triethanolamine. When a basic catalyst is used, the carrier is remarkably trapped by the remaining catalyst, and the electrophotographic characteristics tend to be deteriorated. Therefore, it is desirable to inactivate or remove by neutralizing with an acid or contacting with an adsorbent such as silica gel or an ion exchange resin.

  As the melamine resin and the benzoguanamine resin, various types such as a methylol type in which the methylol group is intact, a full ether type in which all the methylol groups are alkyl etherified, a fluino type, a mixed type of methylol and imino group can be used. Among these, the ether type is desirable from the viewpoint of the stability of the coating solution.

  As the urethane resin, polyfunctional isocyanate, isocyanurate, or blocked isocyanate obtained by blocking these with alcohol or ketone can be used. Among these, from the viewpoint of the stability of the coating solution, a blocked isocyanate or isocyanurate is preferable, and these are preferable because they are overheat-crosslinked with the additive for an electrophotographic photoreceptor of the present invention.

  As the silicone resin, a resin derived from a compound represented by the following general formula (X) can be used.

  These resins can be used alone or in combination of two or more.

  Conductive particles may be added to the protective layer 7 in order to lower the residual potential. Examples of the conductive particles include metals, metal oxides, and carbon black. Of these, metals or metal oxides are more desirable. Examples of the metal include aluminum, zinc, copper, chromium, nickel, silver, and stainless steel, or those obtained by depositing these metals on the surface of plastic particles. Examples of the metal oxide include zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony and tantalum-doped tin oxide, and antimony-doped zirconium oxide. It is done. These can be used alone or in combination of two or more. When two or more types are used in combination, they may be simply mixed, or may be in the form of a solid solution or fusion. From the viewpoint of the transparency of the protective layer 7, the average particle size of the conductive particles is preferably 0.3 μm or less, and particularly preferably 0.1 μm or less.

  In addition, a compound represented by the following general formula (X) is added to the curable resin composition for forming the protective layer 7 in order to control various physical properties such as strength and film resistance of the protective layer 7. You can also.

Si (R ⁵⁰ ) _(4-c) Q _c (X)
[In the above formula (X), R ⁵⁰ represents a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group, Q represents a hydrolyzable group, and c represents an integer of 1 to 4. ]

  Specific examples of the compound represented by the general formula (X) include the following silane coupling agents. Examples of silane coupling agents include tetrafunctional silanes such as tetramethoxysilane and tetraethoxysilane (c = 4); methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, methyltrimethoxyethoxysilane, vinyltri Methoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxy Silane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, (tridecafluoro-1,1,2,2-tetrahydrooctyl L) Triethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, 3- (heptafluoroisopropoxy) propyltriethoxysilane, 1H, 1H, 2H, 2H-perfluoroalkyltriethoxysilane, 1H , 1H, 2H, 2H-perfluorodecyltriethoxysilane, trifunctional alkoxysilanes such as 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (c = 3); dimethyldimethoxysilane, diphenyldimethoxysilane, methyl And bifunctional alkoxysilanes such as phenyldimethoxysilane (c = 2); monofunctional alkoxysilanes such as trimethylmethoxysilane (c = 1), and the like. Trifunctional and tetrafunctional alkoxysilanes are preferable for improving the strength of the film, and monofunctional and bifunctional alkoxysilanes are desirable for improving the flexibility and film formability.

  In addition, a silicon-based hard coat agent produced mainly from these coupling agents can also be used. Commercially available hard coat agents include KP-85, X-40-9740, X-40-2239 (manufactured by Shin-Etsu Silicone), and AY42-440, AY42-441, AY49-208 (manufactured by Toray Dow Corning). Etc.) can be used.

  Further, in the curable resin composition for forming the protective layer 7, a compound having two or more silicon atoms as shown in the following general formula (XI) is used in order to increase the strength of the protective layer 7. Is also desirable.

B- (Si (R ⁵¹ ) _(3-d) Q _d ) ₂ (XI)
[In the above formula (XI), B represents a divalent organic group, R ⁵¹ represents a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group, Q represents a hydrolyzable group, and d represents an integer of 1 to 3. Indicates. ]

  More specifically, as the compound represented by the general formula (XI), the following compounds (XI-1) to (XI-16) can be mentioned as desirable ones. Me represents a methyl group, and Et represents an ethyl group.

  Further, a resin soluble in an alcohol solvent or a ketone solvent may be added for controlling the film characteristics and extending the liquid life. Examples of such resins include polyvinyl butyral resins, polyvinyl formal resins, and polyvinyl acetal resins such as partially acetalized polyvinyl acetal resins in which a part of butyral is modified with formal, acetoacetal, or the like (for example, ESREC B, K manufactured by Sekisui Chemical Co., Ltd.). Etc.), polyamide resin, cellulose resin, phenol resin and the like. In particular, polyvinyl acetal resin is desirable from the viewpoint of improving electrical characteristics.

  Various resins can be added for the purposes of discharge gas resistance, mechanical strength, scratch resistance, particle dispersibility, viscosity control, torque reduction, wear amount control, pot life extension, and the like. In this embodiment, it is desirable to further add a resin that dissolves in alcohol. Examples of resins soluble in alcohol solvents include polyvinyl butyral resins, polyvinyl formal resins, and polyvinyl acetal resins such as partially acetalized polyvinyl acetal resins in which a part of butyral has been modified with formal or acetoacetal (for example, manufactured by Sekisui Chemical Co., Ltd.) ESREC B, K, etc.), polyamide resin, cellulose resin and the like. In particular, polyvinyl acetal resin is desirable from the viewpoint of improving electrical characteristics.

  The weight average molecular weight of the resin is preferably from 2,000 to 100,000, more preferably from 5,000 to 50,000. If the weight average molecular weight is less than 2000, the desired effect tends not to be obtained. If the weight average molecular weight is more than 100,000, the solubility tends to be low and the addition amount is limited, or the film formation tends to be poor during coating. . The addition amount is preferably 1% by mass to 40% by mass, more preferably 1% by mass to 30% by mass, and most preferably 5% by mass to 20% by mass. When the addition amount is less than 1% by mass, it is difficult to obtain a desired effect. When the addition amount is more than 40% by mass, there is a risk of image blurring at high temperature and high humidity. Moreover, although said resin may be used independently, you may mix and use them.

  In order to prolong pot life and control film properties, it is desirable to contain a cyclic compound having a repeating structural unit represented by the following general formula (XII) or a derivative from the compound.

[In the above formula (XII), A ¹ and A ² each independently represent a monovalent organic group. ]
Examples of the cyclic compound having a repeating structural unit represented by the general formula (XII) include commercially available cyclic siloxanes. Specifically, cyclic dimethylcyclosiloxanes such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, 1,3,5-trimethyl-1,3,5- Triphenylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetraphenylcyclotetrasiloxane, 1,3,5,7,9-pentamethyl-1,3,5,7 , 9-pentaphenylcyclopentasiloxane and other cyclic methylphenylcyclosiloxanes, hexaphenylcyclotrisiloxane and other cyclic phenylcyclosiloxanes, and 3- (3,3,3-trifluoropropyl) methylcyclotrisiloxane and other fluorine Atom-containing cyclosiloxanes, methylhydrosiloxa Mixture, pentamethylcyclopentasiloxane, mention may be made of phenyl hydrosilyl group-containing cyclosiloxanes of hydrocyclosiloxane like, cyclic siloxanes and vinyl group-containing cyclosiloxanes such as penta vinyl pentamethylcyclopentasiloxane like. These cyclic siloxane compounds may be used alone or in combination of two or more.

  Further, various particles may be added to the curable resin composition for forming the protective layer 7 in order to control the contamination resistance adhesion, lubricity, hardness and the like on the surface of the electrophotographic photosensitive member.

  An example of the particles may include silicon atom-containing particles. The silicon atom-containing particles are particles containing silicon as a constituent element, and specific examples include colloidal silica and silicone particles. The colloidal silica used as the silicon atom-containing particles has a volume average particle diameter of preferably 1 nm to 100 nm, more preferably 10 nm to 30 nm, and an acidic or alkaline aqueous dispersion, or an organic material such as alcohol, ketone, or ester. What was chosen from what was disperse | distributed in the solvent and generally marketed can be used. The solid content of colloidal silica in the curable resin composition is not particularly limited, but is desirable based on the total solid content in the curable resin composition in terms of film formability, electrical characteristics, and strength. Is used in the range of 0.1% by weight to 50% by weight, more preferably in the range of 0.1% by weight to 30% by weight.

  The silicone particles used as the silicon atom-containing particles are spherical and preferably have a volume average particle diameter of 1 nm to 500 nm, more preferably 10 nm to 100 nm, and the silicone resin particles, the silicone rubber particles, and the silicone surface-treated silica particles. Those selected and generally commercially available can be used.

  Silicone particles are small particles that are chemically inert and excellent in dispersibility in resins, and since the content required to obtain more sufficient properties is low, the crosslinking reaction is not hindered. The surface properties of the photographic photoreceptor can be improved. In other words, in a state in which it is uniformly incorporated into a strong cross-linked structure, it improves the lubricity and water repellency of the surface of the electrophotographic photosensitive member, and maintains good wear resistance and contamination resistance adhesion over a long period of time. Can do. The content of the silicone particles in the curable resin composition is desirably in the range of 0.1% by mass or more and 30% by mass or less, more preferably 0.5%, based on the total solid content in the curable resin composition. The range is from 10% by mass to 10% by mass.

Other particles include fluorine-based particles such as ethylene tetrafluoride, ethylene trifluoride, propylene hexafluoride, vinyl fluoride, vinylidene fluoride, and the 8th Polymer Materials Forum Lecture Proceedings p89. Particles made of a resin obtained by copolymerizing a fluororesin and a monomer having a hydroxyl group, ZnO—Al ₂ O ₃ , SnO ₂ —Sb ₂ O ₃ , In ₂ O ₃ —SnO ₂ , ZnO—TiO ₂ , ZnO Examples thereof include semiconductive metal oxides such as —TiO ₂ , MgO—Al ₂ O ₃ , FeO—TiO ₂ , TiO ₂ , SnO ₂ , In ₂ O ₃ , ZnO, and MgO.

  In addition, oil such as silicone oil can be added in order to control the contamination resistance adhesion, lubricity, hardness and the like of the surface of the electrophotographic photosensitive member. Examples of the silicone oil include silicone oils such as dimethylpolysiloxane, diphenylpolysiloxane, and phenylmethylsiloxane, amino-modified polysiloxane, epoxy-modified polysiloxane, carboxyl-modified polysiloxane, carbinol-modified polysiloxane, methacryl-modified polysiloxane, and mercapto. Examples include reactive silicone oils such as modified polysiloxanes and phenol-modified polysiloxanes. These may be added in advance to the curable resin composition for forming the protective layer 7, or may be impregnated under reduced pressure or increased pressure after producing the photoreceptor.

  Moreover, additives, such as a plasticizer, a surface modifier, antioxidant, and a photodegradation inhibitor, can also be contained. Examples of the plasticizer include biphenyl, biphenyl chloride, terphenyl, dibutyl phthalate, diethylene glycol phthalate, dioctyl phthalate, triphenyl phosphate, methyl naphthalene, benzophenone, chlorinated paraffin, polypropylene, polystyrene, and various fluorohydrocarbons.

  In addition, an antioxidant having a hindered phenol, hindered amine, thioether or phosphite partial structure can be added, which is effective in improving the potential stability and image quality when the environment changes.

  Examples of the antioxidant include the following compounds. For example, hindered phenols include “Sumilizer BHT-R”, “Sumilizer MDP-S”, “Sumilizer BBM-S”, “Sumizer WX-R”, “Sumizer NW”, “Sumizer BP-76”, “ Sumilizer BP-101 "," Sumilizer GA-80 "," Sumilizer GM "," Sumilizer GS "or more manufactured by Sumitomo Chemical Co., Ltd.," IRGANOX1010 "," IRGANOX1035 "," IRGANOX1076 "," IRGANOX1098 "," IRGANOX1098 "," 114 " ”,“ IRGANOX1222 ”,“ IRGANOX1330 ”,“ IRGANOX1425WL ”,“ IRGANOX1 20L "," IRGANOX 245 "," IRGANOX 259 "," IRGANOX 3114 "," IRGANOX 3790 "," IRGANOX 5057 "," IRGANOX 565 "or more, manufactured by Ciba Specialty Chemicals," ADK STAB AO-20 "," ADK STAB AO-30 "," ADEKA STAB " "AO-40", "ADK STAB AO-50", "ADK STAB AO-60", "ADK STAB AO-70", "ADK STAB AO-80", "ADK STAB AO-330" or more manufactured by Asahi Denka. As the hindered amine system, “Sanol LS2626”, “Sanol LS765”, “Sanol LS770”, “Sanol LS744” or more manufactured by Sankyo Lifetech Co., Ltd. "Mark LA57", "Mark LA67", "Mark LA62", "Mark LA68", "Mark LA63" or more manufactured by Asahi Denka, "Sumilyzer TPS" or more manufactured by Sumitomo Chemical Co., Ltd. As a phosphite system manufactured by Sumitomo Chemical Co., Ltd., "Mark 2112", "Mark PEP 8", "Mark PEP 24G", "Mark PEP 36", "Mark 329K", "Mark HP 10" or more Asahi Denka products, especially hindered phenol, hindert Min antioxidant is desirable. Furthermore, these may be modified with a substituent such as an alkoxysilyl group capable of undergoing a crosslinking reaction with the material forming the crosslinked film.

Further, in order to remove the catalyst during synthesis from a resin having a crosslinked structure such as a phenol resin, a melamine resin, or a benzoguanamine resin, the resin is dissolved in an appropriate solvent such as methanol, ethanol, toluene, ethyl acetate, and washed with water. It is desirable to perform a treatment such as reprecipitation using a poor solvent, or to perform treatment using, for example, the materials exemplified below. Such materials include Amberlite 15, Amberlite 200C, Amberlist 15E (above, manufactured by Rohm and Haas), Dowex MWC-1-H, Dowex 88, Dowex HCR-W2 (above, Dow Chemical Co., Ltd.), Levacit SPC-108, Levacit SPC-118 (manufactured by Bayer), Diaion RCP-150H (Mitsubishi Kasei), Sumikaion KC-470, Duolite C26-C, Duolite C-433 Cation exchange resins such as Duolite-464 (manufactured by Sumitomo Chemical Co., Ltd.) and Nafion-H (manufactured by DuPont); Amberlite IRA-400, Amberlite IRA-45 (above, Rohm and Haas) Anion exchange resin such as Zr (O ₃ PCH ₂ CH ₂ SO) ₃ H) ₂ , Th (O ₃ PCH ₂ CH ₂ COOH) An inorganic solid in which a group containing a protonic acid group such as ₂ is bonded to the surface; containing a protonic acid group such as a polyorganosiloxane having a sulfonic acid group Polyorganosiloxanes; heteropolyacids such as cobalt tungstic acid and phosphomolybdic acid; isopolyacids such as niobic acid, tantalum acid and molybdic acid; unitary metal oxides such as silica gel, alumina, chromia, zirconia, CaO and MgO; silica -Composite metal oxides such as alumina, silica-magnesia, silica-zirconia, zeolites; clay minerals such as acid clay, activated clay, montmorillonite, kaolinite; metal sulfates such as LiSO ₄ and MgSO ₄ ; zirconia phosphate , metal phosphates such as lanthanum phosphate; LiNO , Mn (NO ₃₎ metal nitrate such as _2; inorganic group containing an amino group such as solid obtained by reacting aminopropyltriethoxysilane on silica gel is bonded to a surface solid; amino-modified silicone resin And polyorganosiloxanes containing amino groups such as

  In addition, polyglycidyl methacrylate, glycidyl bisphenols, epoxy-containing compounds such as phenol epoxy resins, terephthalic acid, maleic acid, pyromellitic acid, biphenyltetracarboxylic acid are used to adjust film properties such as hardness, adhesion, and flexibility. Acids or the like or anhydrides thereof may be added. The addition amount is desirably 0.05 to 1 part by mass, and more desirably 0.1 to 0.7 part by mass with respect to 1 part by mass of the additive for electrophotographic photoreceptor of the present invention.

  Furthermore, polyvinyl butyral resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin, polyacrylamide resin, Insulating resins such as polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, and polyvinyl pyrrolidone resin can be mixed at a desired ratio. Thereby, the adhesiveness with the electric charge transport layer 6, the coating film defect by heat shrink or repellency, etc. can also be suppressed.

  The protective layer 7 is formed using a coating liquid for forming a protective layer containing the above-described constituent materials. That is, the protective layer 7 is formed by applying a coating liquid for forming a protective layer on the charge transport layer 6 and curing it.

  In the coating solution for forming the protective layer, a solvent such as alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone and methyl ethyl ketone; tetrahydrofuran; ethers such as diethyl ether and dioxane is used as necessary. . In addition to these, various solvents can be used, but in order to apply the dip coating method generally used in the production of electrophotographic photoreceptors, alcohol-based or ketone-based solvents, or mixed solvents thereof Is preferable. The boiling point is preferably 50 to 150 ° C. and can be arbitrarily mixed and used. The amount of the solvent can be set arbitrarily, but if it is too small, it is likely to precipitate, so 0.5 to 30 parts by mass is preferable with respect to a total of 1 part by mass of the solid content contained in the coating liquid for forming the protective layer. Part by mass is more desirable.

  Furthermore, when crosslinking, a curing catalyst may be used in the protective layer forming coating solution. Curing catalysts include bissulfonyldiazomethanes such as bis (isopropylsulfonyl) diazomethane, bissulfonylmethanes such as methylsulfonyl p-toluenesulfonylmethane, sulfonylcarbonyldiazomethanes such as cyclohexylsulfonylcyclohexylcarbonyldiazomethane, 2-methyl Sulfonylcarbonyl alkanes such as 2- (4-methylphenylsulfonyl) propiophenone, nitrobenzyl sulfonates such as 2-nitrobenzyl p-toluenesulfonate, alkyl and aryl sulfonates such as pyrogallol trismethanesulfonate ( g) Benzoin sulfonates such as benzoin tosylate, N- such as N- (trifluoromethylsulfonyloxy) phthalimide. Sulfonyloxyimides, pyridones such as (4-fluorobenzenesulfonyloxy) -3,4,6-trimethyl-2-pyridone, 2,2,2-trifluoro-1-trifluoromethyl-1- ( Photoacid generators such as sulfonic acid esters such as 3-vinylphenyl) -ethyl-4-chlorobenzenesulfonate, onium salts such as triphenylsulfonium methanesulfonate, diphenyliodonium trifluoromethanesulfonate, protonic acids or Lewis acids. Preferred examples include compounds neutralized with Lewis bases, mixtures of Lewis acids and trialkyl phosphates, sulfonic acid esters, phosphate esters, onium compounds, and carboxylic anhydride compounds.

Compounds obtained by neutralizing a protonic acid or Lewis acid with a Lewis base include halogenocarboxylic acids, sulfonic acids, sulfuric acid monoesters, phosphoric acid mono- and diesters, polyphosphoric acid esters, boric acid mono- and diesters, and the like. Various amines such as monoethylamine, triethylamine, pyridine, piperidine, aniline, morpholine, cyclohexylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, or trialkylphosphine, triarylphosphine, trialkylphosphite, triaryl Compounds neutralized with phosphite, as well as NureCure 2500X, 4167, X-47-110, 3525, 5225 commercially available as acid-base blocking catalysts (trade name, King Ndasutori Co., Ltd.), and the like. Examples of the compound obtained by neutralizing a Lewis acid with a Lewis base include compounds obtained by neutralizing a Lewis acid such as BF ₃ , FeCl ₃ , SnCl ₄ , AlCl ₃ , ZnCl ₂ with the above Lewis base.

Examples of the onium compound include triphenylsulfonium methanesulfonate, diphenyliodonium trifluoromethanesulfonate, and the like.
Examples of the carboxylic anhydride compound include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, lauric anhydride, oleic anhydride, stearic anhydride, n-caproic anhydride, n-caprylic anhydride, and n-capric anhydride. , Palmitic anhydride, myristic anhydride, trichloroacetic anhydride, dichloroacetic anhydride, monochloroacetic anhydride, trifluoroacetic anhydride, heptafluorobutyric anhydride, and the like.
Specific examples of Lewis acids include, for example, boron trifluoride, aluminum trichloride, ferrous chloride, ferric chloride, ferrous chloride, ferric chloride, zinc chloride, zinc bromide, stannous chloride. , Metal halides such as stannic chloride, stannous bromide, stannic bromide, organometallic compounds such as trialkylboron, trialkylaluminum, dialkylaluminum halide, monoalkylaluminum halide, tetraalkyltin , Diisopropoxyethyl acetoacetate aluminum, tris (ethyl acetoacetate) aluminum, tris (acetylacetonato) aluminum, diisopropoxy bis (ethyl acetoacetate) titanium, diisopropoxy bis (acetylacetonato) titanium, tetrakis (N-propylacetoacetate Zirconium, Tetrakis (acetylacetonato) zirconium, Tetrakis (ethylacetoacetate) zirconium, Dibutyl-bis (acetylacetonato) tin, Tris (acetylacetonato) iron, Tris (acetylacetonato) rhodium, Bis (acetyl) Acetonato) zinc, tris (acetylacetonato) cobalt metal chelate compounds, dibutyltin dilaurate, dioctyltin ester malate, magnesium naphthenate, calcium naphthenate, manganese naphthenate, iron naphthenate, cobalt naphthenate, copper naphthenate , Zinc naphthenate, zirconium naphthenate, lead naphthenate, calcium octylate, manganese octylate, iron octylate, cobalt octylate, zinc octylate, zirconium octylate, Tin chill acid, lead octylate, zinc laurate, magnesium stearate, aluminum stearate, calcium stearate, cobalt stearate, zinc stearate, and metal soaps such as stearate lead. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Although the usage-amount of these catalysts is not restrict | limited, 0.1-20 mass parts is preferable with respect to the total 100 mass parts of solid content contained in the coating liquid for protective layer formation, and 0.3-10 mass parts is preferable. Particularly preferred.

  When the coating liquid for forming the protective layer is applied onto the charge transport layer 6, the coating methods are blade coating method, Mayer bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating. Ordinary methods such as a method can be used. And after application | coating, the protective layer 7 forms by drying a coating film.

  In addition, in the case of application | coating, when a required film thickness cannot be obtained by one application | coating, a required film thickness can be obtained by apply | coating several times. When performing multiple times of repeated application, the heat treatment may be performed every time of application, or after multiple times of repeated application.

  When the protective layer 7 is formed using a resin having a crosslinked structure, the curing temperature is desirably 100 to 170 ° C., more desirably 100 to 160 ° C. when crosslinking is performed. The curing time is preferably 30 minutes to 2 hours, more preferably 30 minutes to 1 hour, and the heating temperature may be changed to another stage.

  The atmosphere in which the crosslinking reaction is performed can be prevented in a gas atmosphere inert to so-called oxidation such as nitrogen, helium, and argon, thereby preventing deterioration of electrical characteristics. When the crosslinking reaction is performed in an inert gas atmosphere, the curing temperature can be set higher than in an air atmosphere, and the curing temperature is preferably 100 to 180 ° C, more preferably 110 to 160 ° C. Further, the curing time is desirably 30 minutes to 2 hours, and more desirably 30 minutes to 1 hour.

  The thickness of the protective layer 7 is preferably 0.5 to 15 μm, more preferably 1 to 10 μm, and further preferably 1 to 5 μm.

Oxygen permeability at 25 ° C. of the protective layer 7 is preferably not more than ^{4 × 10 12 fm / s ·} Pa, more preferably not more than ^{3.5 × 10 12 fm / s ·} Pa, 3 × 10 More preferably, it is ¹² fm / s · Pa or less.

  Here, the oxygen permeation coefficient is a scale representing the ease of oxygen gas permeation of the layer, but it can also be regarded as a substitute characteristic of the physical gap ratio of the layer if the view is changed. In addition, although the absolute value of the transmittance changes if the type of gas changes, there is almost no reversal of the magnitude relationship between the layers serving as specimens. Therefore, the oxygen permeation coefficient may be interpreted as a measure expressing the general ease of gas permeation.

  That is, when the oxygen permeation coefficient at 25 ° C. of the protective layer 7 satisfies the above conditions, the gas hardly penetrates into the protective layer 7. Therefore, the permeation of the discharge product generated by the image forming process is suppressed, the deterioration of the compound contained in the protective layer 7 is suppressed, the electrical characteristics can be maintained at a high level, and the image quality is improved and the life is extended. It is valid.

  In the electrophotographic photoreceptor 1, when a single-layer type photosensitive layer is formed, the single-layer type photosensitive layer is formed containing a charge generating material and a binder resin. The charge generation material is the same as that used for the charge generation layer in the function separation type photosensitive layer, and the binder resin is a binder resin used for the charge generation layer and the charge transport layer in the function separation type photosensitive layer. Similar ones can be used. The content of the charge generating material in the single-layer type photosensitive layer is preferably 10 to 85% by mass, more preferably 20 to 50% by mass, based on the total solid content in the single-layer type photosensitive layer. A charge transport material or a polymer charge transport material may be added to the single-layer type photosensitive layer for the purpose of improving photoelectric characteristics. The addition amount is preferably 5 to 50% by mass based on the total solid content in the single-layer type photosensitive layer. Moreover, the solvent and coating method used for coating can be the same as those for the above layers. The thickness of the single-layer type photosensitive layer is preferably about 5 to 50 μm, more preferably 10 to 40 μm.

  Next, the developing device 25 described for the developing device 25 develops the electrostatic latent image on the electrophotographic photosensitive member 1 to form a toner image.

The toner used for the developing device 25 will be described. The toner has an average shape factor SF1 (SF1 = ML ² / A × π / 4 × 100, where ML represents the maximum particle length and A represents the projected area of the particle) of 110 to 135. It is more preferable. The average shape factor (SF1) is obtained by measuring an image of toner particles placed on a slide glass with an optical microscope through a video camera, taking it into an image analyzer (LUZEX III, manufactured by NIRECO), and measuring the maximum length of toner (ML ) And the projected area (A) are calculated, and these values are substituted into the above formula to obtain the shape factor. The average shape factor is an average value of the shape factors calculated from the above formula for arbitrary 100 toner particles. The average shape factor indicates the degree of roundness of the toner. The rounder the shape, the more residual toner that passes through the cleaning blade, and the contamination of the charging roll may increase. On the other hand, if the shape is too irregular, the transferability is deteriorated, and there is a case where contamination of the charging roll is increased due to an increase in residual toner.

  Further, the toner preferably has a volume average particle diameter of 5 μm or more and 10 μm or less. If the volume average particle size is too small, the amount of residual toner that passes through the cleaning blade increases, which may increase the contamination of the charging roll. At the same time, the fluidity of the toner may be deteriorated, and it may be difficult to impart sufficient chargeability from the carrier, fogging to the background may occur, and the density reproducibility may be easily lowered. If the volume average particle size is too large, the particle size distribution is also enlarged, resulting in a non-uniform toner charge amount distribution, increasing the amount of reverse polarity toner and increasing the contamination of the charging roll. In addition to being easily generated, the reproducibility and gradation of fine dots may deteriorate.

  The toner is not particularly limited by the production method as long as it satisfies the above average shape factor and volume average particle diameter. For example, the toner may include a binder resin, a colorant, a release agent, and the like. A kneading and pulverizing method in which a charge control agent is added, kneading, pulverizing, and classifying; a method in which the shape of particles obtained by the kneading and pulverizing method is changed by mechanical impact force or thermal energy; Emulsion polymerization of the body, and the resulting dispersion is mixed with a dispersion of a colorant, a release agent and, if necessary, a charge control agent, and then agglomerated and heat-fused to obtain toner particles. Suspension polymerization method in which a polymerizable monomer for obtaining a binder resin, a colorant, a release agent, and a charge control agent, if necessary, are suspended in an aqueous solvent and polymerized; A water-based solution of a resin, a colorant, a release agent, and a solution such as a charge control agent as necessary. Toner is used which is suspended in and produced by a dissolution suspension method in which granulated.

  Further, a known method such as a production method in which the toner obtained by the above method is used as a core, and agglomerated particles are further adhered and heat-fused to give a core-shell structure can be used. The toner production method is preferably a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method in which an aqueous solvent is used from the viewpoint of shape control and particle size distribution control, and an emulsion polymerization aggregation method is particularly preferable.

  The toner base particles are composed of a binder resin, a colorant, and a release agent, and include silica and a charge control agent as necessary.

  Binder resins used for toner base particles include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, etc. Α-methylene aliphatics such as vinyl esters, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate Homopolymers and copolymers of monocarboxylic acid esters, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone Polyester resins by copolymerization of dicarboxylic acids and diols.

  Particularly representative binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. A polymer, polyethylene, polypropylene, a polyester resin, etc. can be mentioned. In addition, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like can also be mentioned.

  In addition, as colorants, magnetic powders such as magnetite and ferrite, carbon black, aniline blue, caryl blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, Lamp Black, Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 can be exemplified as a representative one.

  Typical examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, Fischer tropic wax, montan wax, carnauba wax, rice wax, and candelilla wax.

  As the charge control agent, known ones can be used, and azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups can be used. When the toner is manufactured by a wet manufacturing method, it is preferable to use a material that is difficult to dissolve in water in terms of controlling ionic strength and reducing wastewater contamination. The toner may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material.

  The toner used in the developing device 25 can be manufactured by mixing the toner base particles and the external additive with a Henschel mixer or a V blender. In addition, when the toner base particles are produced by a wet method, external addition can also be performed by a wet method.

  Lubricating particles may be added to the toner used in the developing device 25. Lubricating particles include solid lubricants such as graphite, molybdenum disulfide, talc, fatty acids and fatty acid metal salts, low molecular weight polyolefins such as polypropylene, polyethylene and polybutene, silicones having a softening point upon heating, oleic amides Aliphatic amides such as erucic acid amide, ricinoleic acid amide, stearic acid amide, etc., plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, animals such as beeswax Minerals such as system waxes, montan waxes, ozokerites, ceresins, paraffin waxes, microcrystalline waxes, Fischer-Tropsch waxes, etc., petroleum waxes, and modified products thereof can be used. These can be used individually by 1 type or in combination of 2 or more types. However, the volume average particle size is preferably in the range of 0.1 μm or more and 10 μm or less, and those having the above chemical structure may be pulverized to make the particle sizes uniform. The amount added to the toner is desirably in the range of 0.05% by mass to 2.0% by mass, and more desirably in the range of 0.1% by mass to 1.5% by mass.

  To the toner used in the developing device 25, inorganic particles, organic particles, composite particles obtained by attaching inorganic particles to the organic particles, and the like can be added for the purpose of removing the adhered matter and deteriorated matter on the surface of the electrophotographic photosensitive member. .

  Inorganic particles include silica, alumina, titania, zirconia, barium titanate, aluminum titanate, strontium titanate, magnesium titanate, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, Various inorganic oxides such as manganese oxide, boron oxide, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride, and boron nitride, nitrides, borides, and the like are preferably used.

  In addition, the inorganic particles may be mixed with titanium coupling agents such as tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, bis (dioctylpyrophosphate) oxyacetate titanate, γ- (2- Aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxy Silane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane The treatment may be performed with a silane coupling agent such as run, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, and p-methylphenyltrimethoxysilane. In addition, those hydrophobized with higher fatty acid metal salts such as silicone oil, aluminum stearate, zinc stearate and calcium stearate are also preferably used.

  Examples of the organic particles include styrene resin particles, styrene acrylic resin particles, polyester resin particles, and urethane resin particles.

  The particle diameter is preferably 5 nm to 1000 nm, more preferably 5 nm to 800 nm, and still more preferably 5 nm to 700 nm in terms of volume average average particle diameter. If the volume average particle diameter is less than the lower limit, the polishing ability tends to be lacking. On the other hand, if the volume average particle diameter exceeds the upper limit, the surface of the electrophotographic photosensitive member tends to be damaged. Moreover, it is preferable that the sum of the addition amount of the particle | grains mentioned above and lubricity particle | grains is 0.6 mass% or more.

  Other inorganic oxides added to the toner are small-diameter inorganic oxides with a primary particle size of 40 nm or less for powder flowability, charge control, etc. It is preferable to add a larger-diameter inorganic oxide. As these inorganic oxide particles, known particles can be used, but it is preferable to use silica and titanium oxide in combination for precise charge control. Further, the surface treatment of the small-diameter inorganic particles increases the dispersibility and increases the effect of increasing the powder fluidity. Furthermore, it is also preferable to add carbonates such as calcium carbonate and magnesium carbonate and inorganic minerals such as hydrotalcite in order to remove the discharge purified product.

  In addition, the color toner for electrophotography is used by mixing with a carrier. As the carrier, iron powder, glass beads, ferrite powder, nickel powder, or those having a resin coating on the surface thereof are used. The mixing ratio with the carrier can be set as appropriate.

  The cleaning device 27 includes a fibrous member (roll shape) 27a and a cleaning blade (blade member) 27b.

Although the cleaning device 27 is provided with the fibrous member 27a and the cleaning blade 27b, the cleaning device 27 may be provided with either one. The fibrous member 27a may have a toothbrush shape in addition to the roll shape. Further, the fibrous member 27a may be fixed to the cleaning device main body, may be supported so as to be rotatable, and may be supported so as to be capable of oscillating in the photosensitive member axial direction. As the fibrous member 27a, polyester, nylon, acrylic, etc., cloth-like ones made of ultrafine fibers such as Toraysee (made by Toray Industries), resin fibers such as nylon, acrylic, polyolefin, polyester, etc. are used as a substrate or carpet. The brush-like thing etc. which were flocked to can be mentioned. Further, as the fibrous member 27a, a conductive powder or an ionic conductive agent is added to the above-described material to impart conductivity, or a conductive layer is formed inside or outside of each fiber. Can also be used. When conductivity is imparted, the resistance value of the single fiber is preferably 10 ² Ω or more and 10 ⁹ Ω or less. The fiber thickness of the fibrous member 27a is desirably 30 d (denier) or less, more desirably 20 d or less, and the fiber density is desirably 20,000 fibers / inch ² or more, more desirably 30,000 fibers / inch. inch ² or more.

  The cleaning device 27 is required to remove deposits (for example, discharge products) on the surface of the photoreceptor with a cleaning blade and a cleaning brush. In order to achieve this purpose over a long period of time and stabilize the function of the cleaning member, the cleaning member may be supplied with a lubricating substance (lubricating component) such as metal soap, higher alcohol, wax, silicone oil or the like. desirable.

  For example, when a roll-shaped member is used as the fibrous member 27a, it is desirable to supply a lubricating component to the surface of the electrophotographic photoreceptor by bringing it into contact with a lubricating substance such as metal soap or wax. A normal rubber blade is used as the cleaning blade 27b. As described above, when a rubber blade is used as the cleaning blade 27b, supplying a lubricating component to the surface of the electrophotographic photosensitive member is particularly effective in suppressing chipping and wear of the blade.

  The process cartridge 20 described above is detachable from the image forming apparatus main body, and constitutes the image forming apparatus together with the image forming apparatus main body.

  The exposure device 30 may be any device that exposes the charged electrophotographic photosensitive member 1 to form an electrostatic latent image. Further, it is desirable to use a multi-beam surface emitting laser as the light source of the exposure apparatus 30.

  The transfer device 40 may be any device that transfers the toner image on the electrophotographic photosensitive member 1 to a transfer medium (intermediate transfer member 50). For example, a roll-shaped one that is usually used is used.

  As the intermediate transfer member 50, a belt-like member (intermediate transfer belt) made of polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber or the like having semiconductivity is used. Further, as the form of the intermediate transfer member 50, a drum-like member can be used in addition to the belt-like member. Although there is a direct transfer type image forming apparatus that does not include the intermediate transfer body, the electrophotographic photosensitive member of the present invention is suitable for such an image forming apparatus. The reason is that in a direct transfer type image forming apparatus, paper dust, talc, and the like are generated from the print paper and are likely to adhere to the electrophotographic photosensitive member, and image quality defects due to the attached matter tend to occur. However, according to the electrophotographic photoreceptor of the present invention, it is easy to remove paper dust and talc because of its excellent cleaning properties, and a stable image can be obtained even with a direct transfer type image forming apparatus. it can.

  The transfer medium referred to in the present invention is not particularly limited as long as it is a medium to which a toner image formed on the electrophotographic photoreceptor 1 is transferred. For example, when transferring directly from the electrophotographic photosensitive member 1 to paper or the like, paper or the like is a transfer medium, and when the intermediate transfer member 50 is used, the intermediate transfer member is a transfer medium.

  FIG. 3 is a schematic diagram showing another embodiment of the image forming apparatus of the present invention. In the image forming apparatus 110 shown in FIG. 3, the electrophotographic photosensitive member 1 is fixed to the main body of the image forming apparatus, and the charging device 21, the developing device 25, and the cleaning device 27 are each formed as a cartridge. It is provided independently as a cleaning cartridge.

  In the image forming apparatus 110, the electrophotographic photosensitive member 1 and other devices are separated, and the charging device 21, the developing device 25, and the cleaning device 27 are fixed to the image forming apparatus main body by screws, caulking, adhesion, or welding. It is possible to detach it by the operation by pulling out and pushing in without being done.

  Since the electrophotographic photosensitive member of the present invention is excellent in wear resistance, it may not be necessary to form a cartridge. Therefore, the charging device 21, the developing device 25, or the cleaning device 27 can be detached and attached by an operation by pulling out and pushing in without being fixed to the main body by screws, caulking, adhesion, or welding. The member cost per hit can be reduced. Further, two or more of these devices can be detachable as an integrated cartridge, thereby further reducing the member cost per print.

  The image forming apparatus 110 has the same configuration as that of the image forming apparatus 100 except that the charging device 21, the developing device 25, and the cleaning device 27 are each formed as a cartridge.

  FIG. 4 is a schematic view showing another embodiment of the image forming apparatus of the present invention. The image forming apparatus 120 is a tandem full-color image forming apparatus equipped with four process cartridges 20. In the image forming apparatus 120, four process cartridges 20 are arranged in parallel on the intermediate transfer member 50, and one electrophotographic photosensitive member can be used for one color. The image forming apparatus 120 has the same configuration as that of the image forming apparatus 100 except that it is a tandem system.

  In the tandem-type image forming apparatus 120, the amount of wear of each electrophotographic photosensitive member varies depending on the use ratio of each color, and thus the electrical characteristics of each electrophotographic photosensitive member tend to vary. Along with this, the toner development characteristics gradually change from the initial state, and the hue of the print image changes, so that a stable image cannot be obtained. In particular, in order to reduce the size of the image forming apparatus, a small-diameter electrophotographic photosensitive member tends to be used, and this tendency becomes prominent when one having a diameter of 30 mmφ or less is used. Here, when the configuration of the electrophotographic photosensitive member of the present invention is adopted as the electrophotographic photosensitive member, the surface wear is suppressed even when the diameter is 30 mmφ or less. Therefore, the electrophotographic photosensitive member of the present invention is particularly effective for a tandem type image forming apparatus.

  FIG. 5 is a schematic view showing another embodiment of the image forming apparatus of the present invention. The image forming apparatus 130 shown in FIG. 5 is a so-called four-cycle image forming apparatus that forms toner images of a plurality of colors with one electrophotographic photosensitive member. The image forming apparatus 130 includes a photosensitive drum 1 that is rotated by a driving device (not shown) at a predetermined rotational speed in the direction of arrow A in the figure, and above the photosensitive drum 1 is a photosensitive member. A charging device 21 for charging the outer peripheral surface of the drum 1 is provided.

  Further, an exposure device 30 having a surface emitting laser array as an exposure light source is disposed above the charging device 21. The exposure device 30 modulates a plurality of laser beams emitted from a light source in accordance with an image to be formed and deflects the laser beams in the main scanning direction so that the axis of the photosensitive drum 1 is on the outer peripheral surface of the photosensitive drum 1. Scan in parallel. Thereby, an electrostatic latent image is formed on the outer peripheral surface of the charged photosensitive drum 1.

  A developing device 25 is disposed on the side of the photosensitive drum 1. The developing device 25 includes a roll-shaped container that is rotatably arranged. Four containers are formed inside the container, and developing units 25Y, 25M, 25C, and 25K are provided in each container. Each of the developing units 25Y, 25M, 25C, and 25K includes a developing roll 26, and stores therein toners of yellow (Y), magenta (M), cyan (C), and black (K), respectively.

  The full-color image is formed by the image forming apparatus 130 while the photosensitive drum 1 is rotated four times. That is, while the photosensitive drum 1 rotates four times, the charging device 21 charges the outer peripheral surface of the photosensitive drum 1, and the exposure device 30 includes Y, M, C, and K image data representing a color image to be formed. Scanning the outer peripheral surface of the photosensitive drum 1 with the laser beam modulated according to any one of the above is repeated while switching the image data used for modulation of the laser beam every time the photosensitive drum 1 rotates. Further, the developing device 25 operates the developing device corresponding to the outer peripheral surface in a state where any of the developing rolls 26 of the developing devices 25Y, 25M, 25C, and 25K corresponds to the outer peripheral surface of the photosensitive drum 1. The photosensitive drum 1 is the one that develops the electrostatic latent image formed on the outer peripheral surface of the photosensitive drum 1 to a specific color and forms a toner image of the specific color on the outer peripheral surface of the photosensitive drum 1. Each time it rotates, the process is repeated while rotating the container so that the developing unit used for developing the electrostatic latent image is switched. As a result, every time the photosensitive drum 1 rotates, the Y, M, C, and K toner images are sequentially formed on the outer peripheral surface of the photosensitive drum 1 so as to overlap each other. When the drum 1 rotates four times, a full-color toner image is formed on the outer peripheral surface of the photosensitive drum 1.

  Further, an endless intermediate transfer belt 50 is disposed below the photosensitive drum 1. The intermediate transfer belt 50 is wound around rolls 51, 53, and 55, and is arranged so that the outer peripheral surface is in contact with the outer peripheral surface of the photosensitive drum 1. The rolls 51, 53, and 55 are rotated by a driving force of a motor (not shown) and rotate the intermediate transfer belt 50 in the direction of arrow B in FIG.

  A transfer device (transfer device) 40 is disposed on the opposite side of the photosensitive drum 1 across the intermediate transfer belt 50, and the toner image formed on the outer peripheral surface of the photosensitive drum 1 is intermediate transferred by the transfer device 40. The image is transferred onto the image forming surface of the belt 50.

  A lubricant supply device 29 and a cleaning device 27 are disposed on the outer peripheral surface of the photosensitive drum 1 on the opposite side of the developing device 25 with the photosensitive drum 1 interposed therebetween. When the toner image formed on the outer peripheral surface of the photosensitive drum 1 is transferred to the intermediate transfer belt 50, the lubricant is supplied to the outer peripheral surface of the photosensitive drum 1 by the lubricant supply device 29, and the The area that has held the transferred toner image is cleaned by the cleaning device 27.

  A sheet receiver 60 is disposed below the intermediate transfer belt 50, and a plurality of sheets P as recording materials are accommodated in the sheet receiver 60 in a stacked state. A take-out roll 61 is disposed obliquely above and to the left of the paper receiver 60, and a roll pair 63 and a roll 65 are arranged in this order on the downstream side in the take-out direction of the paper P by the take-out roll 61. The recording paper located in the uppermost position in the stacked state is taken out from the paper receiver 60 when the take-out roll 61 is rotated, and is conveyed by the roll pair 63 and the roll 65.

  A transfer device 42 is disposed on the opposite side of the roll 55 with the intermediate transfer belt 50 interposed therebetween. The paper P conveyed by the roll pair 63 and the roll 65 is fed between the intermediate transfer belt 50 and the transfer device 42, and the toner image formed on the image forming surface of the intermediate transfer belt 50 is transferred by the transfer device 42. . A fixing device 44 having a pair of fixing rolls is disposed downstream of the transfer device 42 in the transport direction of the paper P. The paper P on which the toner image is transferred is transferred to the paper P by the fixing device 44. After being fused and fixed, it is discharged out of the image forming apparatus 130 and placed on a paper discharge tray (not shown).

  The configuration of the process cartridge of the present invention and the image forming apparatus of the present invention are not particularly limited, and may be a known configuration.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

(Example 1)
A cleaning roll was prepared in which an elastic layer made of a polyester urethane foam having a rebound resilience of 22%, a hardness of 195 N, and a number of bubbles of 50/25 mm was provided on the core.

  Then, the obtained cleaning roll was charged with a charging roll (roll diameter: 14 mm, roll length: 320 mm, shaft diameter: 8 mm, shaft length: 332 mm, and the roll was composed of an adhesive layer, an elastic layer, and a resistance layer on the shaft. The charging device arranged so as to be in contact with the same is applied to a modified DocuCenter Color a 450 manufactured by Fuji Xerox. At the same time, a developer using a toner having a volume average particle size of 6.0 μm and an average shape factor SF1 of 130 and a toner were mounted on the developing device, and a print test of 5000 sheets was performed. Table 2 shows the surface state observation results and print image observation results of the charging roll in the 5000-sheet print test.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: Sanester 22, Sanyo Kasei Kogyo Co., Ltd.), 30 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, made by Nippon Polyurethane Co., Ltd.) 31 parts (Kao Co., Ltd. tertiary amine catalyst) 1 part by mass, water (foaming agent) 2.0 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2 parts by mass Thus, the intended foamed urethane raw material was prepared. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

(Example 2)
A cleaning roll was prepared in which an elastic layer made of a polyester urethane foam having a rebound resilience of 17%, a hardness of 155 N, and a number of bubbles of 45/25 mm was provided on the core.

  Then, the charging device in which the obtained cleaning roll was placed in contact with the charging roll (similar to Example 1) was mounted on a DocuCenter Color a 450 modified machine manufactured by Fuji Xerox. At the same time, a developer using a toner having a volume average particle size of 6.0 μm and an average shape factor SF1 of 130 and a toner were mounted on the developing device, and a print test of 5000 sheets was performed. Table 2 shows the surface state observation results and print image observation results of the charging roll in the 5000-sheet print test.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: San Ester 22, Sanyo Chemical Industries), 25 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, manufactured by Nippon Polyurethane), Kaolinizer No. 31 (Kao Co., Ltd. tertiary amine catalyst) 0.7 parts by mass, water (foaming agent) 1.5 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2 parts by mass The target foamed urethane raw material was adjusted by caulking. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

(Example 3)
A cleaning roll was prepared in which an elastic layer made of a polyester urethane foam having a rebound resilience of 28%, a hardness of 225 N, and a number of bubbles of 55/25 mm was provided on the core.

  Then, the charging device in which the obtained cleaning roll was placed in contact with the charging roll was mounted on a DocuCenter Color a 450 modified machine manufactured by Fuji Xerox. At the same time, a developer using a toner having a volume average particle size of 6.0 μm and an average shape factor SF1 of 130 and a toner were mounted on the developing device, and a print test of 5000 sheets was performed. Table 2 shows the surface state observation results and print image observation results of the charging roll in the 5000-sheet print test.

-Preparation of cleaning roll-
100 parts by mass of a polyester polyol (trade name: Sanester 22, Sanyo Chemical Industries), 35 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, manufactured by Nippon Polyurethane), Kaolinizer No. 31 (Kao Co., Ltd. tertiary amine catalyst) 1.3 parts by mass, water (foaming agent) 2.5 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2 parts by mass The target foamed urethane raw material was adjusted by caulking. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

Example 4
A cleaning roll was prepared in which an elastic layer made of a polyester urethane foam having a rebound resilience of 22%, a hardness of 195 N, and a number of bubbles of 50/25 mm was provided on the core.

  Then, the charging device in which the obtained cleaning roll was placed in contact with the charging roll was mounted on a DocuCenter Color a 450 modified machine manufactured by Fuji Xerox. At the same time, a developer using a toner having a volume average particle size of 5.2 μm and an average shape factor SF1 of 130 and a toner were mounted on the developing device, and a print test of 5000 sheets was performed. Table 2 shows the surface state observation results and print image observation results of the charging roll in the 5000-sheet print test.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: Sanester 22, Sanyo Kasei Kogyo Co., Ltd.), 30 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, made by Nippon Polyurethane Co., Ltd.) 31 parts (Kao Co., Ltd. tertiary amine catalyst) 1 part by mass, water (foaming agent) 2.0 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2 parts by mass Thus, the intended foamed urethane raw material was prepared. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

(Example 5)
A cleaning roll was prepared in which an elastic layer made of a polyester urethane foam having a rebound resilience of 22%, a hardness of 195 N, and a number of bubbles of 50/25 mm was provided on the core.

  Then, the charging device in which the obtained cleaning roll was placed in contact with the charging roll was mounted on a DocuCenter Color a 450 modified machine manufactured by Fuji Xerox. At the same time, a developer using a toner having a volume average particle size of 8.0 μm and an average shape factor SF1 of 130 and a toner were mounted on the developing device, and a print test of 5000 sheets was performed. Table 2 shows the surface state observation results and print image observation results of the charging roll in the 5000-sheet print test.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: San Ester 22, Sanyo Chemical Industries), 30 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, manufactured by Nippon Polyurethane Co., Ltd.) 31 parts (Kao Co., Ltd. tertiary amine catalyst) 1 part by mass, water (foaming agent) 2.0 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2 parts by mass Thus, the intended foamed urethane raw material was prepared. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

(Example 6)
A cleaning roll was prepared in which an elastic layer made of a polyester urethane foam having a rebound resilience of 22%, a hardness of 195 N, and a number of bubbles of 50/25 mm was provided on the core.

  Then, the charging device in which the obtained cleaning roll was placed in contact with the charging roll was mounted on a DocuCenter Color a 450 modified machine manufactured by Fuji Xerox. At the same time, a developer using a toner having a volume average particle size of 6.0 μm and an average shape factor SF1 of 115 and a toner were mounted on the developing device, and a print test of 5000 sheets was performed. Table 2 shows the surface state observation results and print image observation results of the charging roll in the 5000-sheet print test.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: San Ester 22, Sanyo Chemical Industries), 30 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, manufactured by Nippon Polyurethane Co., Ltd.) 31 parts (Kao Co., Ltd. tertiary amine catalyst) 1 part by mass, water (foaming agent) 2.0 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2 parts by mass Thus, the intended foamed urethane raw material was prepared. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

(Example 7)
A cleaning roll was produced in which an elastic layer made of a polyether urethane foam having a rebound resilience of 22%, a hardness of 195 N, and a number of bubbles of 50/25 mm was provided on the core.

  Then, the charging device in which the obtained cleaning roll was placed in contact with the charging roll was mounted on a DocuCenter Color a 450 modified machine manufactured by Fuji Xerox. At the same time, a developer using a toner having a volume average particle size of 6.0 μm and an average shape factor SF1 of 130 and a toner were mounted on the developing device, and a print test of 5000 sheets was performed. Table 2 shows the surface state observation results and print image observation results of the charging roll in the 5000-sheet print test.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: Sanester 22, Sanyo Kasei Kogyo Co., Ltd.), 30 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, made by Nippon Polyurethane Co., Ltd.) 31 parts (Kao Co., Ltd. tertiary amine catalyst) 1 part by mass, water (foaming agent) 2.0 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2 parts by mass Thus, the intended foamed urethane raw material was prepared. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

(Example 8)
A cleaning roll was prepared in which an elastic layer made of a polyester urethane foam having a rebound resilience of 22%, a hardness of 195 N, and a number of bubbles of 35/25 mm was provided on the core as prepared below.

  Then, the charging device in which the obtained cleaning roll was placed in contact with the charging roll was mounted on a DocuCenter Color a 450 modified machine manufactured by Fuji Xerox. At the same time, a developer using a toner having a volume average particle size of 6.0 μm and an average shape factor SF1 of 130 and a toner were mounted on the developing device, and a print test of 5000 sheets was performed. Table 2 shows the surface state observation results and print image observation results of the charging roll in the 5000-sheet print test.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: Sanester 22, Sanyo Kasei Kogyo Co., Ltd.), 30 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, made by Nippon Polyurethane Co., Ltd.) By blending 1 part by mass of 31 (Kao Co., Ltd. tertiary amine catalyst), 1 part by mass of water (foaming agent) and 2 parts by mass of polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.), The target foamed urethane material was adjusted. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

Example 9
A cleaning roll was produced in which an elastic layer made of a polyester urethane foam having a rebound resilience of 22%, a hardness of 195 N, and a number of bubbles of 65/25 mm was provided on the core.

  Then, the charging device in which the obtained cleaning roll was placed in contact with the charging roll was mounted on a DocuCenter Color a 450 modified machine manufactured by Fuji Xerox. At the same time, a developer using a toner having a volume average particle size of 6.0 μm and an average shape factor SF1 of 130 and a toner were mounted on the developing device, and a print test of 5000 sheets was performed. Table 2 shows the surface state observation results and print image observation results of the charging roll in the 5000-sheet print test.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: Sanester 22, Sanyo Kasei Kogyo Co., Ltd.), 30 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, made by Nippon Polyurethane Co., Ltd.) By blending 1 part by mass of 31 (Kao Co., Ltd. tertiary amine catalyst), 3 parts by mass of water (foaming agent), 2 parts by mass of polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.), The target foamed urethane material was adjusted. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

(Example 10)
A cleaning roll was prepared in which an elastic layer made of a polyester urethane foam having a rebound resilience of 22%, a hardness of 195 N, and a number of bubbles of 50/25 mm was provided on the core.

  Then, the charging device in which the obtained cleaning roll was placed in contact with the charging roll was mounted on a DocuCenter Color a 450 modified machine manufactured by Fuji Xerox. At the same time, a developer using a toner having a volume average particle size of 3.5 μm and an average shape factor SF1 of 130 and a toner were mounted on the developing device, and a print test of 5000 sheets was performed. Table 2 shows the surface state observation results and print image observation results of the charging roll in the 5000-sheet print test.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: San Ester 22, Sanyo Chemical Industries), 30 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, manufactured by Nippon Polyurethane Co., Ltd.) 31 parts (Kao Co., Ltd. tertiary amine catalyst) 1 part by mass, water (foaming agent) 2.0 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2 parts by mass Thus, the intended foamed urethane raw material was prepared. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

(Example 11)
A cleaning roll was prepared in which an elastic layer made of a polyester urethane foam having a rebound resilience of 22%, a hardness of 195 N, and a number of bubbles of 50/25 mm was provided on the core.

  Then, the charging device in which the obtained cleaning roll was placed in contact with the charging roll was mounted on a DocuCenter Color a 450 modified machine manufactured by Fuji Xerox. At the same time, a developer using a toner having a volume average particle diameter of 12 μm and an average shape factor SF1 of 130 and a toner were mounted on the developing device, and a print test of 5000 sheets was performed. Table 2 shows the surface state observation results and print image observation results of the charging roll in the 5000-sheet print test.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: Sanester 22, Sanyo Kasei Kogyo Co., Ltd.), 30 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, made by Nippon Polyurethane Co., Ltd.) 31 parts (Kao Co., Ltd. tertiary amine catalyst) 1 part by mass, water (foaming agent) 2.0 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2 parts by mass Thus, the intended foamed urethane raw material was prepared. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

Example 12
A cleaning roll was prepared in which an elastic layer made of a polyester urethane foam having a rebound resilience of 22%, a hardness of 195 N, and a number of bubbles of 50/25 mm was provided on the core.

  Then, the charging device in which the obtained cleaning roll was placed in contact with the charging roll was mounted on a DocuCenter Color a 450 modified machine manufactured by Fuji Xerox. At the same time, a developer using a toner having a volume average particle size of 6.0 μm and an average shape factor SF1 of 140 and a toner were mounted on the developing device, and a print test of 5000 sheets was performed. Table 2 shows the surface state observation results and print image observation results of the charging roll in the 5000-sheet print test.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: Sanester 22, Sanyo Kasei Kogyo Co., Ltd.), 30 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, manufactured by Nippon Polyurethane Co., Ltd.) 31 (Kao Co., Ltd. tertiary amine catalyst) 1 part by mass, water (foaming agent) 2.0 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2 parts by mass. Thus, the intended foamed urethane raw material was prepared. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and kept at 60 ° C. for 5 minutes to foam and harden. Thereafter, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

(Comparative Example 1)
The same test as in Example 1 was performed using the same cleaning roll as in Example 1 except that the impact resilience was 10%. The results are shown in Table 2.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: Sanester 22, Sanyo Chemical Industries), 15 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, manufactured by Nippon Polyurethane Co., Ltd.) 31 (Kao Co., Ltd. tertiary amine catalyst) 0.5 parts by mass, water (foaming agent) 2.0 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2 parts by mass The target foamed urethane raw material was adjusted by caulking. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

(Comparative Example 2)
The same test as in Example 1 was performed using the same cleaning roll as in Example 1 except that the rebound resilience was 45% produced as follows. The results are shown in Table 2.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: Sanester 22, Sanyo Kasei Kogyo Co., Ltd.), 45 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, made by Nippon Polyurethane Co., Ltd.) 31 (Kao Co., Ltd. tertiary amine catalyst) 1.5 parts by mass, water (foaming agent) 2.0 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2.0 parts by mass The desired foamed urethane raw material was adjusted by blending. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

(Comparative Example 3)
The same test as in Example 1 was performed using the same cleaning roll as in Example 1 except that the rebound elastic modulus hardness was 125 N, which was produced as follows. The results are shown in Table 2.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: Sanester 22, Sanyo Chemical Industries), 17 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, manufactured by Nippon Polyurethane Co., Ltd.) 31 (Kao Co., Ltd. tertiary amine catalyst) 0.4 parts by mass, water (foaming agent) 2.0 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2.0 parts by mass The desired foamed urethane raw material was adjusted by blending. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

(Comparative Example 4)
The same test as in Example 1 was performed using the same cleaning roll as in Example 1 except that the rebound elastic modulus hardness was 240 N produced as follows. The results are shown in Table 2.

-Preparation of cleaning roll-
100 parts by mass of polyester polyol (trade name: Sanester 22, Sanyo Kasei Kogyo Co., Ltd.), 45 parts by mass of 4,4′-diphenylmethane diisocyanate (trade name: Millionate MTL, made by Nippon Polyurethane Co., Ltd.) 31 (Kao Co., Ltd. tertiary amine catalyst) 2 parts by mass, water (foaming agent) 2.0 parts by mass, polyoxyethylene alkyl ether potassium phosphate (foam stabilizer Kao Co., Ltd.) 2.0 parts by mass The target foamed urethane raw material was adjusted by caulking. Next, using a foamed urethane raw material having such a composition, an appropriate amount is poured into a mold in which a shaft (diameter 6 mm, length 330 mm) is previously placed, and held at 60 ° C. for 5 minutes to foam and harden. After that, the roll was removed from the mold and the roll surface was polished to prepare the intended cleaning roll.

  As described above, in this embodiment, the substances adhering to the surface of the electric member can be efficiently removed, and good cleaning performance can be maintained over a long period of time. It can be seen that it is possible to prevent the occurrence of image defects due to contamination due to.

  It can also be seen that the cleaning characteristics are improved by setting the number of bubbles in the elastic layer, the volume average particle diameter of the toner, and the average shape factor in the cleaning roll within a predetermined range.

1 is a schematic diagram illustrating a preferred embodiment of a charging device of the present invention. 1 is a schematic diagram showing a preferred embodiment of an image forming apparatus of the present invention. It is a schematic diagram which shows other suitable embodiment of the image forming apparatus of this invention. It is a schematic diagram which shows other suitable embodiment of the image forming apparatus of this invention. It is a schematic diagram which shows other suitable embodiment of the image forming apparatus of this invention. 1 is a schematic cross-sectional view showing a preferred embodiment of an electrophotographic photoreceptor. It is a schematic cross-sectional view showing another preferred embodiment of the electrophotographic photosensitive member. It is a schematic cross-sectional view showing another preferred embodiment of the electrophotographic photosensitive member. It is a schematic cross-sectional view showing another preferred embodiment of the electrophotographic photosensitive member. It is a schematic cross-sectional view showing another preferred embodiment of the electrophotographic photosensitive member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electrophotographic photoreceptor, 2 ... Electroconductive support body, 3 ... Photosensitive layer, 4 ... Undercoat layer, 5 ... Charge generation layer, 6 ... Charge transport layer, 7 ... Protective layer, 8 ... Single layer type photosensitive layer, 20: Process cartridge, 100, 110, 120, 130: Image forming apparatus

Claims (6)

The core,
An elastic layer provided on the outer peripheral surface of the core body, the elastic layer having an open cell structure and including a urethane foam having a rebound resilience of 15% to 30% and a hardness of 150N to 230N When,
A cleaning roll for a charging member, comprising:   The charging member cleaning roll according to claim 1, wherein the number of bubbles in the open cell structure is in a range of 40/25 mm to 58/25 mm.   The cleaning roll for a charging member according to claim 1, wherein the urethane foam is a polyester-based urethane foam. A roll-shaped charging member for charging the member to be charged;
A charging member cleaning roll disposed in contact with an outer peripheral surface of the charging member, wherein the charging member cleaning roll according to any one of claims 1 to 3,
A charging device comprising: A charging device for charging an image carrier, the charging device according to claim 4,
The image carrier, a developing device for developing the electrostatic latent image formed on the image carrier with toner to form a toner image, and the toner remaining on the surface of the image carrier At least one selected from the group consisting of cleaning devices;
A process cartridge comprising: An image carrier,
A charging device for charging the image carrier, the charging device according to claim 4,
An exposure device for forming an electrostatic latent image on the charged image carrier;
A developing device for developing the electrostatic latent image formed on the image carrier with toner to form a toner image;
A transfer device for transferring the toner image to a transfer target;
An image forming apparatus comprising:

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